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Objective: Sudomotor symptoms are a common component of diabetic autonomic neuropathy, but the pathology of sudomotor innervation and its relationship with glycemic control have remained obscured.Research Design and Methods: We enrolled 42 patients (26 males and 16 females aged 56.64 ± 12.67 years) with diabetic neuropathy defined by symmetric distally predominant sensory symptoms, abnormal nerve conduction studies, and reduced intraepidermal nerve fiber density in the leg. Skin biopsies of the distal leg were immunostained with antiprotein gene product 9.5 for nerve fibers and counterstained with Congo red for sweat glands. Sweat gland innervation index (SGII) was quantified with a new computerized area-based morphometric system.Results: Protein gene product 9.5(+) nerve terminals surrounded secretory coils of the sweat glands in the skin of control subjects. Sudomotor denervation was present in diabetic patients, manifesting as depletion of periglandular nerve fibers with lower SGII compared with 42 age- and sex-matched control subjects (2.54 ± 1.87 vs. 4.68 ± 1.51%, P < 0.001). The SGII was correlated with HbA(1c) (P = 0.011) and was lower in patients with anhidrosis of the feet compared with those with normal sweating of the feet (0.82 ± 0.69 vs. 3.00 ± 1.81%, P = 0.001). Sudomotor denervation was concordant with cardiac autonomic dysfunction as assessed with reduced heart rate variability (P = 0.003).Conclusions: Sudomotor denervation is a significant presentation of diabetic neuropathy, and the SGII was associated with HbA(1c). A skin biopsy offers a structural assessment of sudomotor innervation. [ABSTRACT FROM AUTHOR]

Gross anatomy and neuroanatomy are fundamental subjects in medical education. However, learning different anatomical terms and understanding the complexity of the subjects are often challenging for medical students. At National Taiwan University, the 2020-2021 cohort adopted a face-to-face (F2F) learning strategy for gross anatomy and neuroanatomy lecture and laboratory courses until May 17, 2021. After the aforementioned date, the same cohort learned the rest of the gross anatomy and neuroanatomy courses via asynchronous online learning. This study aimed to evaluate the benefits of and students' preferences for F2F and asynchronous online learning strategies in learning gross anatomy and neuroanatomy. A survey with closed-ended and open-ended questions was used to quantitatively and qualitatively explore medical students' learning preferences for two teaching strategies in gross anatomy and neuroanatomy. The results identified different learning preferences among students in learning gross anatomy and neuroanatomy-satisfied with both learning strategies, satisfied with only F2F learning strategy, satisfied with only asynchronous online learning strategy, and satisfied with neither learning strategy. The survey results with closed-ended and open-ended questions showed that medical students preferred F2F learning for anatomical laboratory courses but favored asynchronous online learning for neuroanatomical laboratory courses. In addition, medical students considered peer discussion more critical in learning gross anatomy than neuroanatomy. These findings provide valuable information about medical students' preference for gross anatomy and neuroanatomy courses, which anatomy teachers can consider when planning to enhance their curriculum in the future., (© 2024 American Association of Clinical Anatomists and British Association of Clinical Anatomists.)

Conventional diagnostic methods for glaucoma primarily rely on non-dynamic fundus images and often analyze features such as the optic cup-to-disc ratio and abnormalities in specific retinal locations like the macula and fovea. However, hyperspectral imaging techniques focus on detecting alterations in oxygen saturation within retinal vessels, offering a potentially more comprehensive approach to diagnosis. This study explores the diagnostic potential of hyperspectral imaging for glaucoma by introducing a novel hyperspectral imaging conversion technique. Digital fundus images are transformed into hyperspectral representations, allowing for a detailed analysis of spectral variations. Spectral regions exhibiting differences are identified through spectral analysis, and images are reconstructed from these specific regions. The Vision Transformer (ViT) algorithm is then employed for classification and comparison across selected spectral bands. Fundus images are used to identify differences in lesions, utilizing a dataset of 1291 images. This study evaluates the classification performance of models using various spectral bands, revealing that the 610-780 nm band outperforms others with an accuracy, precision, recall, F1-score, and AUC-ROC all approximately at 0.9007, indicating its superior effectiveness for the task. The RGB model also shows strong performance, while other bands exhibit lower recall and overall metrics. This research highlights the disparities between machine learning algorithms and traditional clinical approaches in fundus image analysis. The findings suggest that hyperspectral imaging, coupled with advanced computational techniques such as the ViT algorithm, could significantly enhance glaucoma diagnosis. This understanding offers insights into the potential transformation of glaucoma diagnostics through the integration of hyperspectral imaging and innovative computational methodologies.

It can be difficult for some students to learn three-dimensional anatomical structure concepts. While virtual reality (VR) systems have been reported as helpful for learning, there has been scarce research on either VR teaching strategies or the influence of visually induced motion sickness (VIMS) in the context of large anatomy classes (i.e., over 100 students). The study thus aimed to (1) establish a VR anatomy instruction video for a large class; (2) determine how many students experience VIMS when watching a VR anatomy instruction video; (3) evaluate the influence of VIMS on VR anatomy video-based learning; and (4) examine whether a small screen size alleviates VIMS. Laboratory course students viewing a VR anatomy instruction video about the vascular system were invited to participate in the questionnaire survey. Anatomy faculty and staff participated in an experimental trial to determine whether small screen size could alleviate VIMS. The Likert scale survey revealed that students reported the VR strategy as advantageous and appropriate for large classes, but that it cannot replace practical dissection. Of the total participants, 32% reported experiencing VIMS, and 40% of those experiencing VIMS agreed that this could negatively impact their learning through a VR anatomy instruction video. Adjusting the screen size from large to small significantly delayed the onset of VIMS. In conclusion, the VR anatomy instruction video strategy is feasible and helpful for large classes, but educators should consider VIMS when planning their use of this teaching approach., (© 2024 The Authors. Anatomical Sciences Education published by Wiley Periodicals LLC on behalf of American Association for Anatomy.)

Pro-inflammatory macrophages (M1-polarized) play a crucial role in neuroinflammation and neuropathic pain following nerve injury. Redirecting macrophage polarization toward anti-inflammatory (M2-polarized) phenotypes offers a promising therapeutic strategy. Recognized for their anti-inflammatory and immunomodulatory properties, probiotics are becoming a focal point of research. This study investigated the effects of Lactobacillus plantarum on macrophage polarization, nerve protection, and neuropathic pain behavior following chronic constriction injury (CCI) of the median nerve. Rats received daily oral doses of L. plantarum for 28 days before and 14 days after CCI. Subsequently, behavioral and electrophysiological assessments were performed. The M1 marker CD86 levels, M2 marker CD206 levels, and concentrations of pro-inflammatory and anti-inflammatory cytokines in the injured median nerve were assessed. L. plantarum administration effectively reduced neuropathic pain behavior and the Firmicutes to Bacteroidetes ratio after CCI. Moreover, L. plantarum treatment increased serum short-chain fatty acids (SCFAs) levels, preserved myelination of the injured median nerve, and suppressed injury-induced discharges. In CCI rats treated with L. plantarum, there was a reduction in CD86 and pro-inflammatory cytokine levels, accompanied by an increase in CD206 and the release of anti-inflammatory cytokines. Furthermore, receptors for anti-inflammatory cytokines were localized on Schwann cells, and their expression was significantly upregulated in the injured nerves of CCI rats receiving L. plantarum. In conclusion, L. plantarum shifts macrophage phenotypes from M1 to M2 by promoting the production of SCFAs and enhancing the release of anti-inflammatory cytokines. Ultimately, this process preserves nerve fiber integrity and impedes the onset of neuropathic pain., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to declare. Part of the Graphical Abstract was created with biorender.com., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Introduction: Modified teaching strategies (MTS), asynchronous online teaching and smaller dissection groups, were applied to a gross anatomy course for dental students in the National Taiwan University in April 2020 in response to the COVID-19 pandemic. This study aimed to investigate the effects and perceptions of MTS on dental students., Materials and Methods: Scores for anatomy examinations for 2018-2019 (without MTS) and 2019-2020 (with MTS) cohorts were compared to explore the effect on academic performance. Moreover, questionnaire from the 2019-2020 cohort was analysed to determine dental students' perceptions about MTS., Results: The lecture performance in the final examination of the second semester for the 2019-2020 cohort was significantly higher than that of the first semester (pre-COVID-19) and that for the 2018-2019 cohort. However, the laboratory performance in the midterm examination of the second semester for the 2019-2020 cohort was significantly lower than that for the 2018-2019 cohort and showed no difference in the final examination of the first semester. The questionnaires revealed that the majority of students displayed positive attitudes towards MTS and agreed with the importance of peer discussion during laboratory dissection., Conclusions: Asynchronous online learning for anatomy lecture may be beneficial for dental students; however, a smaller dissection group accompanied by reduced peer discussion may temporarily exert negative effects on their laboratory performance at the beginning of the application. Furthermore, more dental students exhibited positive perceptions towards smaller dissection groups. These findings could illuminate the learning condition of dental students in anatomy education., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: Glia (i.e., astrocyte and microglia) activation in the central nervous system plays a critical role in developing neuropathic pain. Microglia can be activated into proinflammatory (M1) and anti-inflammatory (M2) phenotypes. Switching microglial polarization from M1 to M2 phenotypes represents a novel therapeutic strategy for neuropathic pain. Curcumin has been widely used for its anti-inflammatory and immunomodulatory effects. This study investigated effects of curcumin on astrocyte activation and microglia polarization in the cuneate nucleus (CN) and development of neuropathic pain behavior after chronic constriction injury (CCI) of the median nerve., Methods: Rats were fed with curcumin once daily at a dose of 40, 80, or 120 mg/kg 30 min before and until 7 d after median nerve CCI. Subsequently, mechanical allodynia and thermal hyperalgesia were evaluated using von Frey filaments and plantar tests, respectively. The levels of astrocyte marker, monoclonal glial fibrillary acidic protein; microglia marker, ionized calcium-binding adapter molecule 1; M1 marker, CD86; and M2 marker, CD206 in the cuneate nucleus were determined. Enzyme-linked immunosorbent assay was applied to measure cytokine concentrations., Results: Curcumin administration dose-dependently reduced mechanical allodynia and thermal hyperalgesia and decreased monoclonal glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 immunoreactivity in the ipsilateral cuneate nucleus after CCI. On ultrastructural observation, curcumin treatment was associated with fewer features of activated astrocytes and microglia. Furthermore, CCI rats given curcumin exhibited a decline in CD86 immunoreactivity and proinflammatory cytokine levels but an increase in CD206 immunoreactivity and release of anti-inflammatory cytokines., Conclusions: In our findings, curcumin switches microglial phenotypes from M1 to M2 by suppressing astrocytic activation, reducing proinflammatory cytokine release, promoting anti-inflammatory cytokine production, and contributing to relief of neuropathic pain., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Registered nurses are required for high-quality healthcare. Thus, the anatomy course is essential regarding professional knowledge of the human body during the nursing training process. However, previous studies have indicated that anatomy teaching time and anatomy teachers were reduced and insufficient. Therefore, to improve the learning of practical anatomy in response to these difficulties, a bilingual National Taiwan University web-based anatomy atlas (NTU-WAA) was created as a cross-platform application and its feasibility was evaluated., Methods: The comparison of anatomy examination scores between nursing students of two cohorts (66 from the 2018-2019 cohort, whom was without NTU-WAA application; 54 from the 2019-2020 cohort, to whom NTU-WAA was offered) and the evaluation of questionnaires collected from nursing students of the 2019-2020 cohort and 4 anatomy teachers were carried out to define the feasibility of this strategy., Results: Results obtained by nursing students for the 2019-2020 cohort showed a significant increase in anatomy learning performance compared with that of the 2018-2019 cohort with reference to the laboratory midterm [2018-2019 cohort vs. 2019-2020 cohort, mean (standard deviation, SD): 77.20 (16.14) vs. 81.80 (12.03); p = 0.043], the laboratory final examination [59.68 (15.28) vs. 80.35 (13.74); p < 0.001] and the theory final examination [80.85 (10.10) vs. 84.33 (6.925); p = 0.017]. Moreover, results of the questionnaires indicated that the new bilingual cross-platform atlas was highly accepted by students and teachers., Conclusions: The NTU-WAA, a bilingual web-based atlas, was evaluated as a beneficial anatomy-learning tool that may enhance self-study of nursing students with consequent amelioration of their anatomy-related performance in both theoretical and laboratory examinations. This reflection suggests the future implementation of the bilingual web-based atlas on a large scale., (© 2022. The Author(s).)

Due to the Covid-19 pandemic, National Taiwan University anatomy teachers adopted asynchronous online video teaching and reduced the size of anatomy laboratory groups in April 2020. The aim of this study was to investigate the impact of these changes on medical students' learning. Before Covid-19, the performance of the 2019-2020 cohort was significantly better than that of the 2018-2019 cohort. However, the implementation of modified teaching strategies significantly lowered the laboratory midterm score of the 2019-2020 cohort in the second semester. Conversely, the final laboratory examination score of the 2019-2020 cohort was significantly higher than that of the 2018-2019 cohort. Through correlation analysis, lecture and laboratory examination scores were highly correlated. Additionally, the difference in lecture and laboratory z-scores between two cohorts, the Likert scale survey and free-text feedback of the 2019-2020 cohort, were conducted to show the impact of modified teaching strategies. There were several important findings in this study. First, the change in teaching strategies may temporarily negatively influence medical students to learn anatomy. Besides, analyzing the performance of laboratory assessments could be a complementary strategy to evaluate online assessments. Applying lecture examination scores to predict laboratory performance was a feasible way to identify students who may have difficulty in learning practical dissection. Finally, reducing group size together with reduced peer discussion may have a negative effect on learning cadaver dissection for students with low academic performance. These findings should be taken into consideration when anatomy teachers apply new teaching strategies in anatomy courses., (© 2022 American Association for Anatomy.)

In this study, we investigated whether melatonin treatment prevents development of neuropathic pain via suppression of glial mitogen-activated protein kinases (MAPKs) activation in the cuneate nucleus (CN) in a lysophosphatidylcholine (LPC)-induced median nerve demyelination neuropathy model. Rats were fed orally with melatonin once a day at a dose of 37.5, 75, or 150 mg/kg 30 min before until 3 days after LPC treatment. Subsequently, behavioral tests were conducted on these animals, and immunohistochemistry and immunoblotting were used for qualitative and quantitative analysis of glia and MAPKs, including ERK, JNK, and p38, activation. Enzyme-linked immunosorbent assays were applied to measure pro-inflammatory cytokine responses. Furthermore, intra-CN microinjection of S26131 (MT 1 receptor antagonist), 4P-PDOT (MT 2 receptor antagonist), or prazosin (MT 3 receptor antagonist) were performed to investigate the association between melatonin receptor subtypes and effects of melatonin on demyelination neuropathy. LPC treatment of the median nerve induced a significant increase in glial fibrillary acidic protein (GFAP; an astrocyte marker) and ED1 (an activated microglia marker) immunoreactivity in the ipsilateral CN and led to development of neuropathic pain behavior. Inspection of GFAP-immunoreactive astrocytes revealed that astrocytic hypertrophy, but not proliferation, contributed to increased GFAP immunoreactivity. Double immunofluorescence showed that both GFAP-immunoreactive astrocytes and ED1-immunoreactive microglia co-expressed p-ERK, p-JNK, and p-p38 immunoreactivity. Melatonin administration dose-dependently reduced neuropathic pain behavior, decreased glial and MAPKs activation, and diminished the release of pro-inflammatory cytokines in the ipsilateral CN after LPC treatment. Furthermore, 4P-PDOT, but not S26131 or prazosin, antagonized the therapeutic effects of melatonin. In conclusion, administration of melatonin, via its cognate MT 2 receptor, inhibited activation of glial MAPKs, production of pro-inflammatory cytokines, and development of demyelination-induced neuropathic pain behavior., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Sepsis-associated encephalopathy (SAE) is frequently encountered in critically ill patients. Hyperglycemia is a common phenomenon among patients with sepsis, and glycemic control improves patient outcomes. Therefore, here, we aimed to explore whether glycemic control using insulin inhibits the pro-inflammatory cytokine response and glial activation in the cerebrum and is concomitantly associated with the relief of SAE. Using cecal ligation and puncture (CLP), sepsis was induced in male Sprague-Dawley rats. The CLP rats were administered intravenous glucose or subjected to subcutaneous insulin implant within the first hour after CLP. The survival rate, blood glucose (BG) values, and behavioral expression were assessed daily for 5 days after CLP. At day 5 after CLP, electroencephalography (EEG) recordings and blood-brain barrier (BBB) permeability testing were performed. Immunohistochemistry, immunoblotting, and enzyme-linked immunosorbent assays were used to evaluate glial activation and the pro-inflammatory cytokine response qualitatively and quantitatively, respectively. The glucose-treated CLP rats (BG > 390 mg/dL) exhibited a decline in survival rate; insensitivity to mechanical and thermal stimuli; slowed EEG activity; and an increase in BBB permeability, pro-inflammatory cytokine (TNF-α, IL-1β, and IL-6) levels, and glial activation (astrocytes and microglia) in the cerebral tissues compared with CLP rats (BG ~ 270 mg/dL). Double-immunofluorescence showed that activated astrocytes and microglia co-expressed phosphorylated nuclear factor kappa B and mitogen-activated protein kinases, respectively. Furthermore, glycemic control using insulin therapy maintained the BG at 120-160 mg/dL and inhibited the production of pro-inflammatory cytokines and glial activation in the cerebrum of septic rats. In addition, the survival rate, sensory threshold, EEG activity, and BBB permeability recovered to near-normal levels in septic rats after insulin therapy. Taken together, the results of this study elucidated the pathophysiological alterations in brains subjected to sepsis, especially regarding glycemic control. These findings improve our understanding of SAE and support the importance of glycemic control in sepsis., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The world-to-chip interface is an essential yet intriguing part of making and employing microfluidic devices. A user-friendly connector could be expensive or difficult to make. We fabricated two ports of microfluidic chips with easily available materials including Teflon blocks, double adhesive films, coverslips, and transparency films. By using a mini grinder, coverslips were drilled to form small holes for the fluid passages between port and chip. Except for the double adhesive films, the resultant ports are durable and re-useable. The DK1 port, contains a mini three-way switch which allows users to handle fluid by a tube-connected pump, or by a manual pipette for the sample of trace amount. The other port, the DK2 port, provides secured tube-connections. Importantly, we invented a bridge made of craft cutter-treated transparency films and double adhesive films to mediate liquid flow between DK2 port and chip. With the use of a bridge, users do not need to design new ports for new chips. Also, individual chips could be linked by a bridge to form a chip array. We successfully applied DK1 port on a microfluidic chip where green fluorescent protein was immobilized. We used DK2 port on an array of fish chips where the embryos of zebra fish developed.

Neuroprotective effects of erythropoietin (EPO) on peripheral nerve injury remain uncertain. This study investigated the efficacy of EPO in attenuating median nerve chronic constriction injury (CCI)-induced neuropathy. Animals received an intraneural injection of EPO at doses of 1,000, 3,000, or 5,000 units/kg 15 min before median nerve CCI. Afterwards, the behavioral and electrophysiological tests were conducted. Immunohistochemistry and immunoblotting were used for qualitative and quantitative analysis of microglial and mitogen-activated protein kinases (MAPKs), including p38, JNK, and ERK, activation. Enzyme-linked immunosorbent assay and microdialysis were applied to measure pro-inflammatory cytokine and glutamate responses, respectively. EPO pre-treatment dose-dependently ameliorated neuropathic pain behavior, decreased microglial and MAPKs activation, and diminished the release of pro-inflammatory cytokines and glutamate in the ipsilateral cuneate nucleus after CCI. Moreover, EPO pre-treatment preserved myelination of the injured median nerve on morphological investigation and suppressed injury-induced discharges. We also observed that EPO receptor (EPOR) expression was up-regulated in the injured nerve after CCI. Double immunofluorescence showed that EPOR was localized to Schwann cells. Furthermore, siRNA-mediated knockdown of EPOR expression eliminated the therapeutic effects of EPO on attenuating the microglial and MAPKs activation, pro-inflammatory cytokine responses, injury discharges, and neuropathic pain behavior in CCI rats. In conclusion, binding of EPO to its receptors on Schwann cells maintains myelin integrity and blocks ectopic discharges in the injured median nerve, that in the end contribute to attenuation of neuropathic pain via reducing glutamate release from primary afferents and inhibiting activation of microglial MAPKs and production of pro-inflammatory cytokines., (© 2018 Wiley Periodicals, Inc.)

In this study, we investigated temporal changes in galanin receptor type 2 (GalR2) expression in NF200-, galanin-, neuropeptide Y (NPY)-, and neuronal nitric oxide synthase (nNOS)-like immunoreactive (LI) dorsal root ganglion (DRG) neurons after median nerve chronic constriction injury (CCI), and the effects of GalR2 on c-Fos expression in the cuneate nucleus (CN). Double immunofluorescence labeling methods were used to appraise changes in GalR2 expression in NF200-LI, galanin-LI, NPY-LI, and nNOS-LI DRG neurons after CCI. The von Frey assay was used to assess the efficiency of intraplantar administration of saline, M871 (a GalR2 antagonist), or AR-M1896 (a GalR2 agonist) on neuropathic signs of rats with CCI. The effects of alterations in c-Fos expression were assessed in all treatments. The percentage of GalR2-LI neurons in lesioned DRGs increased and peaked at 1 week after CCI. We further detected that percentages of GalR2-LI neurons labeled for NF200, galanin, NPY, and nNOS significantly increased following CCI. Furthermore, M871 remarkably attenuated tactile allodynia, but the sensation was slightly aggravated by AR-M1896 after CCI. Consequentially, after electrical stimulation of the CCI-treated median nerve, the number of c-Fos-LI neurons in the cuneate nucleus (CN) was significantly reduced in the M871 group, whereas it increased in the AR-M1896 group. These results suggest that activation of GalR2, probably through NPY or nitric oxide, induces c-Fos expression in the CN and transmits mechanical allodynia sensations to the thalamus., Competing Interests: The authors have declared that no competing interests exist.

Background: Epidemiological studies have shown that ambient air pollution is closely associated with increased respiratory inflammation and decreased lung function. Particulate matters (PMs) are major components of air pollution that damages lung cells. However, the mechanisms remain to be elucidated. This study examines the effects of PMs on intercellular adhesion molecule-1 (ICAM-1) expression and the related mechanisms in vitro and in vivo., Result: The cytotoxicity, reactive oxygen species (ROS) generation, and monocyte adherence to A549 cells were more severely affected by treatment with O-PMs (organic solvent-extractable fraction of SRM1649b) than with W-PMs (water-soluble fraction of SRM1649b). We observed a significant increase in ICAM-1 expression by O-PMs, but not W-PMs. O-PMs also induced the phosphorylation of AKT, p65, and STAT3. Pretreating A549 cells with N-acetyl cysteine (NAC), an antioxidant, attenuated O-PMs-induced ROS generation, the phosphorylation of the mentioned kinases, and the expression of ICAM-1. Furthermore, an AKT inhibitor (LY294002), NF-κB inhibitor (BAY11-7082), and STAT3 inhibitor (Stattic) significantly down-regulated O-PMs-induced ICAM-1 expression as well as the adhesion of U937 cells to epithelial cells. Interleukin-6 (IL-6) was the most significantly changed cytokine in O-PMs-treated A549 cells according to the analysis of the cytokine antibody array. The IL-6 receptor inhibitor tocilizumab (TCZ) and small interfering RNA for IL-6 significantly reduced ICAM-1 secretion and expression as well as the reduction of the AKT, p65, and STAT3 phosphorylation in O-PMs-treated A549 cells. In addition, the intratracheal instillation of PMs significantly increased the levels of the ICAM-1 and IL-6 in lung tissues and plasma in WT mice, but not in IL-6 knockout mice. Pre-administration of NAC attenuated those PMs-induced adverse effects in WT mice. Furthermore, patients with chronic obstructive pulmonary disease (COPD) had higher plasma levels of ICAM-1 and IL-6 compared to healthy subjects., Conclusion: These results suggest that PMs increase ICAM-1 expression in pulmonary epithelial cells in vitro and in vivo through the IL-6/AKT/STAT3/NF-κB signaling pathway.

Background: Mechanisms underlying neuropathic pain relief by the neurosteroid allopregnanolone remain uncertain. We investigated if allopregnanolone attenuates glial extracellular signal-regulated kinase (ERK) activation in the cuneate nucleus (CN) concomitant with neuropathic pain relief in median nerve chronic constriction injury (CCI) model rats., Methods: We examined the time course and cellular localization of phosphorylated ERK (p-ERK) in CN after CCI. We subsequently employed microinjection of a mitogen-activated protein kinase kinase (ERK kinase) inhibitor, PD98059, to clarify the role of ERK phosphorylation in neuropathic pain development. Furthermore, we explored the effects of allopregnanolone (by mouth), intra-CN microinjection of γ-aminobutyric acid type A receptor antagonist (bicuculline) or γ-aminobutyric acid type B receptor antagonist (phaclofen) plus allopregnanolone, and allopregnanolone synthesis inhibitor (medroxyprogesterone; subcutaneous) on ERK activation and CCI-induced behavioral hypersensitivity., Results: At 7 days post-CCI, p-ERK levels in ipsilateral CN were significantly increased and reached a peak. PD98059 microinjection into the CN 1 day after CCI dose-dependently attenuated injury-induced behavioral hypersensitivity (withdrawal threshold [mean ± SD], 7.4 ± 1.1, 8.7 ± 1.0, and 10.3 ± 0.8 g for 2.0, 2.5, and 3.0 mM PD98059, respectively, at 7 days post-CCI; n = 6 for each dose). Double immunofluorescence showed that p-ERK was localized to both astrocytes and microglia. Allopregnanolone significantly diminished CN p-ERK levels, glial activation, proinflammatory cytokines, and behavioral hypersensitivity after CCI. Bicuculline, but not phaclofen, blocked all effects of allopregnanolone. Medroxyprogesterone treatment reduced endogenous CN allopregnanolone and exacerbated nerve injury-induced neuropathic pain., Conclusions: Median nerve injury-induced CN glial ERK activation modulated the development of behavioral hypersensitivity. Allopregnanolone attenuated glial ERK activation and neuropathic pain via γ-aminobutyric acid type A receptors. Reduced endogenous CN allopregnanolone after medroxyprogesterone administration rendered rats more susceptible to CCI-induced neuropathy.

With the progress of science, technology and medicine, the proportion of elderly people in society has gradually increased over the years. Thus, the medical care and health issues of this population have drawn increasing attention. In particular, among the common medical problems of the elderly, the occurrence of cataracts has been widely observed. In this study, we developed retinal imaging technology by establishing a human eye module with ray tracing. Periodic hole arrays with different degrees were constructed on the anterior surface of the lens to emulate the eyesight decline caused by cataracts. Then, we successfully predicted the incidence of cataracts among people with myopia ranging from -3.0 D to -9.0 D. Results show that periodic hole arrays cause severe eyesight decline when they are centralized in the visual center. However, the wide distribution of these arrays on the anterior surface of the lens would not significantly affect one's eyesight.

In this study, we investigated the role of nitric oxide (NO) in lysophosphatidylcholine (LPC) induced peripheral neuropathy by the use of nitric oxide synthase (NOS) inhibitors and NO donor. We found that LPC treatment of the median nerve induced neuropathic pain behaviors (allodynia and hyperalgesia) and nerve demyelination. Immunohistochemistry revealed that the amounts of neuronal NOS-like immunoreative (nNOS-LI) neurons in both the dorsal root ganglion (DRG) and cuneate nucleus (CN) increased and peaked at 1 week after LPC treatment. Following electrical stimulation of the LPC-treated nerve, the number of c-Fos-LI neurons in the ipsilateral CN also increased in a dose-dependent manner following LPC injection and peaked at 1 week. Administration of L-NAME (Nω-Nitro-L-arginine methyl ester) or 7-NI (7-nitroindazole) 1 week after 4% LPC injection attenuated tactile allodynia and thermal hyperalgesia. However, the application of the NO donor S-Nitroso-N-acetylpenicillamine (SNAP) only exacerbated thermal hyperalgesia. After electrical stimulation of the LPC-treated median nerve, the number of c-Fos-LI neurons in the CN diminished in the L-NAME and 7-NI groups, but increased in the SNAP group. Taken together, our findings suggest that advanced NO made by the dramatically increased number of nNOS in the DRG and CN might be involved in the neuropathic sensation and boosted neuronal activity in the CN after LPC treatment., (Copyright © 2013 Elsevier Inc. All rights reserved.)

This study examined the relationship between changes in GABA transmission and behavioral abnormalities after median nerve transection. Following unilateral median nerve transection, the percentage of GABA-like immunoreactive neurons in the cuneate nucleus and that of GABA(B) receptor-like immunoreactive neurons in the dorsal root ganglion in the injured side decreased and reached a nadir at 4 weeks after median nerve transection. Four weeks after bilateral median nerve transection and intraperitoneal application with saline, baclofen (2 mg kg⁻¹), or phaclofen (2 mg kg⁻¹) before unilateral electrical stimulation of the injured median nerve, we investigated the level of neuropeptide Y release and c-Fos expression in the stimulated side of the cuneate nucleus. The neuropeptide Y release level and the number of c-Fos-like immunoreactive neurons in the baclofen group were significantly attenuated, whereas those in the phaclofen group had increased compared to the saline group. These findings indicate that median nerve transection reduces GABA transmission, promoting injury-induced neuropeptide Y release and consequently evoking c-Fos expression in cuneate nucleus neurons. Furthermore, this study used the CatWalk method to assess behavioral abnormalities in rats following median nerve transection. These abnormalities were reversed by baclofen treatment. Overall, the results suggest that baclofen treatment block neuropeptide Y release, subsequently lessening c-Fos expression in cuneate neurons and consequently attenuating neuropathic signal transmission to the thalamus., (Copyright © 2012 Wiley Periodicals, Inc.)

Patients suffering from sensory neuropathy due to skin denervation frequently have paradoxical manifestations of reduced nociception and neuropathic pain. However, there is a lack of satisfactory animal models to investigate these phenomena and underlying mechanisms. We developed a mouse system of neuropathy induced by resiniferatoxin (RTX), a capsaicin analog, and examined the functional significance of P2X3 receptor in neuropathic pain. From day 7 of RTX neuropathy, mice displayed mechanical allodynia (p<0.0001) and thermal hypoalgesia (p<0.0001). After RTX treatment, dorsal root ganglion (DRG) neurons of the peripherin type were depleted (p=0.012), while neurofilament (+) DRG neurons were not affected (p=0.62). In addition, RTX caused a shift in neuronal profiles of DRG: (1) increased in P2X3 receptor (p=0.0002) and ATF3 (p=0.0006) but (2) reduced TRPV1 (p=0.036) and CGRP (p=0.015). The number of P2X3(+)/ATF3(+) neurons was linearly correlated with mechanical thresholds (p=0.0017). The peripheral expression of P2X3 receptor in dermal nerves was accordingly increased (p=0.016), and an intraplantar injection of the P2X3 antagonists, A-317491 and TNP-ATP, relieved mechanical allodynia in a dose-dependent manner. In conclusion, RTX-induced sensory neuropathy with upregulation of P2X3 receptor for peripheral sensitization of mechanical allodynia, which provides a new therapeutic target for neuropathic pain after skin denervation., (Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.)

Aims: This study aimed to investigate temporal changes in glycine and its receptor expressions in cuneate neurons after median nerve transection (MNT), and the effects of glycine on neuropeptide Y (NPY) release and c-Fos expression in the cuneate nucleus (CN)., Main Methods: Immunohistochemistry methods were used to appraise changes of glycine- and GlyR-like immunoreactive (LI) neurons in the CN after MNT. The alterations in NPY and c-Fos expressions were used to assess the effects of saline, glycine or strychnine treatment. The CatWalk method was used to assess the efficiency of glycine treatment on the neuropathic signs of rats with MNT., Key Findings: Approximately half of GlyR-LI neurons were fluorogold-labeled cuneothalamic projection neurons in the CN. Following MNT, the number of GlyR-LI neurons significantly decreased in the injured side of CN at 2 and 4 weeks, but the number of glycine-LI neurons remained unchanged. Four weeks after MNT given with electrical stimulation, strychnine significantly decreased the NPY reduction level in the stimulated side CN compared to that of the saline group. However, numbers of c-Fos-LI neurons in the glycine and strychnine groups were both significantly less than that in the saline group. But the paw print width and area in CatWalk analysis showed only a moderate recovery., Significance: We conjecture that glycine increases glycine-mediated postsynaptic inhibition of cuneate neurons, and also blocks GABAergic neurons containing GlyRs which mediate presynaptic inhibition causing temperate NPY release. Consequently, the compromise results showed a weak reduction in c-Fos expression and a slight amelioration of neuropathic behaviors., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Our previous study demonstrated that pigment epithelium-derived factor (PEDF) plays an important role in the proliferation and migration of human aortic smooth muscle cells (HASMCs). In the present study, we examined whether PEDF inhibited platelet-derived growth factor (PDGF)-stimulated HASMC migration and proliferation. PEDF dose-dependently reduced PDGF-induced HASMC migration and proliferation in vitro and also arrested cell cycle progression in the G0/G1 phase, and this was associated with decreased expression of cyclin D1, cyclin E, CDK2, CDK4, and p21(Cip1) and increased expression of the cyclin-dependent kinase inhibitor p27(Kip1). The antiproliferative and antimigratory effects of PEDF were partially blocked by the PPARγ antagonist GW9662, but not by the PPARα antagonist MK886. In in vivo studies, the femoral artery of C57BL/6 mice was endothelial-denuded and the mice injected intravenously with PEDF or vehicle. After 2 weeks, both the neointima/media area ratio and cell proliferation (proliferating cell nuclear antigen-positive cells) in the neointima were significantly reduced and again these effects were partially reversed by GW9662 pretreatment. Our data show that PEDF increases PPARγ activation, preventing entry of HASMCs into the cell cycle in vitro and reducing the neointimal area and cell proliferation in the neointima in vivo. Thus, PEDF may represent a safe and effective novel target for the prevention and treatment of vascular proliferative diseases., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

In this study, we investigated whether nitric oxide (NO) modulated injury-induced neuropeptide Y (NPY) releasing and c-Fos expression in the cuneate nucleus (CN) after median nerve transection (MNT). We first examined the temporal changes of neuronal nitric oxide synthase (nNOS) expression in the dorsal root ganglion (DRG) and CN after MNT. Following MNT, the amounts of nNOS-like immunoreactive (nNOS-LI) neurons in the DRG and CN significantly increased as compared with those of the sham-operated rats. Furthermore, 4 weeks after MNT, the increases of nNOS-LI neurons in the DRG and CN were attenuated by pre-emptive lidocaine treatment in a dose-dependent manner. Finally, 4 weeks after MNT, pre-stimulation administration of L-NAME (N (ω)-Nitro-L: -arginine methyl ester) or 7-NI (7-nitroindazole) suppressed the amount of NPY release from the stimulated terminals and thus attenuated c-Fos expression in the CN. Our data implied that NO would modulate neuronal activity in the DRG and CN both after MNT.

To investigate the contribution of peptidergic intraepidermal nerve fibers (IENFs) to nociceptive responses after depletion of the thermal-sensitive receptor, transient receptor potential vanilloid subtype 1 (TRPV1), we took advantage of a resiniferatoxin (RTX)-induced neuropathy which specifically affected small-diameter dorsal root ganglion (DRG) neurons and their corresponding nerve terminals in the skin. Thermal hypoalgesia (p<0.001) developed from RTX-treatment day 7 (RTXd7) and became normalized from RTXd56 to RTXd84. Substance P (SP)(+) and TRPV1(+) neurons were completely depleted (p = 0.0001 and p<0.0001, respectively), but RTX had a relatively minor effect on calcitonin gene-related peptide (CGRP)(+) neurons (p = 0.029). Accordingly, SP(+) (p<0.0001) and TRPV1(+) (p = 0.0008) IENFs were permanently depleted, but CGRP(+) IENFs (p = 0.012) were only transiently reduced and had recovered by RTXd84 (p = 0.83). The different effects of RTX on peptidergic neurons were attributed to the higher co-localization ratio of TRPV1/SP than of TRPV1/CGRP (p = 0.029). Thermal hypoalgesia (p = 0.0018) reappeared with an intraplantar injection of botulinum toxin type A (botox), and the temporal course of withdrawal latencies in the hot-plate test paralleled the innervation of CGRP(+) IENFs (p = 0.0003) and CGRP contents in skin (p = 0.01). In summary, this study demonstrated the preferential effects of RTX on depletion of SP(+) IENFs which caused thermal hypoalgesia. In contrast, the skin was reinnervated by CGRP(+) IENFs, which resulted in a normalization of nociceptive functions.

This study investigates the effects of lidocaine pre-emptive treatment on neuropathic pain behavior, injury discharges of nerves, neuropeptide Y (NPY) and c-Fos expression in the cuneate nucleus (CN) after median nerve chronic constriction injury (CCI). Behavior tests demonstrated that the pre-emptive lidocaine treatment dose dependently delayed and attenuated the development of mechanical allodynia within a 28-day period. Electrophysiological recording was used to examine the changes in injury discharges of the nerves. An increase in frequency of injury discharges was observed and peaked at postelectrical stimulation stage in the presaline group, which was suppressed by lidocaine pre-emptive treatment in a dose-dependent manner. Lidocaine pretreatment also reduced the number of injury-induced NPY-like immunoreactive (NPY-LI) fibers and c-Fos-LI neurons within the CN in a dose-dependent manner. Furthermore, the mean number of c-Fos-LI neurons in the CN was significantly correlated to the NPY reduction level and the sign of mechanical allodynia following CCI.

Previous studies have demonstrated that following intratympanic gentamicin application in the guinea pigs, vestibular evoked myogenic potentials (VEMPs) were absent regardless of stimulation mode using either air-conducted sound (ACS) stimuli or galvanic vestibular stimulation (GVS). Ultrastructurally, both type I hair cells and their calyx terminals were distorted in the saccular macula. However, little is known about the toxic effects of gentamicin on the vestibular ganglion (VG). In this study, absent ACS- and GVS-VEMPs were noted in all the gentamicin-treated ears (100%), which were confirmed by the substantial loss of sensory hair cells in the saccular macula. Moreover, dramatic up-regulation of growth associated protein-43 (GAP-43) expression was detected in the ipsilateral VG neurons. The mean percentage of substance P-like immunoreactive (SP-LI) neurons in the treated VG (81.8±1.9%) was significantly higher than that in the control VG (68.6±3.3%). Conversely, the mean percentage of neuropeptide Y-like immunoreactive (NPY-LI) neurons in the treated VG (13.7±3.8%) was dramatically lower than that in the control VG (49.0±3.8%). Double labeling results shown 82% of SP-LI and 16% of NPY-LI neurons coexpressed with GAP-43, suggested that SP accumulating coincided with NPY decreasing in regenerating VG neurons after gentamicin treatment. Overall, the changes in SP and NPY expression in VG neurons after gentamicin treatment were like to those in the superior cervical ganglion following sympathectomy., (Copyright © 2010 Elsevier B.V. All rights reserved.)

In this study we examined the temporal changes in neuropeptide Y (NPY) expression in dorsal root ganglion (DRG) neurons and cuneate nucleus (CN) in streptozotocin (STZ)-induced diabetic rats with or without median nerve transection (MNT). Numerous NPY-like immunoreactive (NPY-LI) neurons and fibers were detected in the DRG and CN of the diabetic MNT (DMNT) rats respectively, but not in those with diabetes-alone. Following MNT, the time-course of NPY expression pattern in the diabetic DRG and CN was similar and both peaked at 2 weeks, which was earlier than those in the non-diabetic MNT rats. Consequently, the expression of neurotrophin-3 (NT-3) immunoreactivity in DRG neurons was coincidentally decreased and reached the nadir at 2 weeks in the diabetic MNT rats, which was also earlier than that in the non-diabetic MNT rats. Following electrical stimulation of the injured nerves, the number of NPY-LI fibers became attenuated and the induced c-Fos-LI cells concurrently appeared in the ipsilateral CN. In the diabetic CN, the number of c-Fos-LI cells also peaked at 2 weeks after MNT, which was consistent with the temporal pattern of changes in NPY expression. The results suggest that in diabetes, MNT induced NPY expression via the reduction of NT-3, and electrical stimulation of the injured median nerve evoked the release of NPY and accordingly more c-Fos-LI cells were identified in the CN. Furthermore, this study demonstrated early NPY and c-Fos expression in the diabetic rats after MNT, suggesting that the development of neuropathic signs may be advanced in hyperglycemic rats.

Objective: The aim of this investigation carried out with guinea pigs was to study the possible effects of a gentamicin treatment on the saccular macula and on its afferent vestibular ganglion neurons., Methods: The gentamicin-induced impairment was analyzed using vestibular-evoked myogenic potentials (VEMPs) elicited by both click and galvanic vestibular stimulations (GVS). Fifty microl of saline or gentamicin solution (40 mg/ml) was dropped over the round window membrane of the right (control) and left (lesion) cochleae, respectively. Four weeks after surgery, the VEMPs elicited with clicks and GVS were evaluated for each animal. Then, the animals were sacrificed in order to perform morphological and anti-Nav1.8 immunocytochemical analyses., Results: Click- and GVS-VEMPs were obtained in all of the controls, whereas no potentials were obtained from gentamicin-treated animals. Lesions of sensory cells were observed in the saccular macula. In the injured vestibular ganglion, the percentage of voltage-gated sodium channel Nav1.8-like immunoreactive (Nav1.8-LI) neurons was significantly lower (38.9+/-0.7) than that (53.6+/-3.2) calculated in controls., Conclusions: Gentamicin-induced impairments of the saccular macula and afferents of guinea pigs can be evaluated by recording both click- and GVS-VEMPs. Both tests provide information on the sacculo-collic reflex pathway and could help a clinical diagnosis of gentamicin intoxication by conventional eardrops in the patient with a perforated eardrum., (2009 Elsevier Inc. All rights reserved.)

In this study, we examined the relationship between astrocyte activation in the cuneate nucleus (CN) and behavioral hypersensitivity after chronic constriction injury (CCI) of the median nerve. In addition, we also examined the effects of pre-emptive treatment with a number of drugs on astrocyte activation and hypersensitivity development in this model. Using immunohistochemistry and immunoblotting, little glial fibrillary acidic protein (GFAP; an astrocyte marker) immunoreactivity was detected in the CN of the normal rats. As early as 3 days after CCI, there was a significant increase in GFAP immunoreactivity in the lesion side of CN, and this reached a maximum at 7 days, and was followed by a decline. Counting of GFAP-immunoreactive astrocytes revealed that astrocytic hypertrophy, but not proliferation, contributes to increased GFAP immunoreactivity. Furthermore, microinjection of the glial activation inhibitor, fluorocitrate, into the CN at 3 days after CCI attenuated injury-induced behavioral hypersensitivity in a dose-dependent manner. These results suggest that median nerve injury-induced astrocytic activation in the CN modulated the development of behavioral hypersensitivity. Animals received MK-801 (glutamate N-methyl-d-aspartate (NMDA) receptor antagonist), clonidine (alpha(2)-adrenoreceptor agonist), tetrodotoxin (TTX, sodium channel blocker) or lidocaine (local anesthetic) 30 min prior to median nerve CCI. Pre-treatment with MK-801, TTX, and 2% lidocaine, but not clonidine, attenuated GFAP immunoreactivity and behavioral hypersensitivity following median nerve injury. In conclusion, suppressing reactions to injury, such as the generation of ectopic discharges and activation of NMDA receptors, can decrease astrocyte activation in the CN and attenuate neuropathic pain sensations., (Copyright 2009 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.)

We assessed the effects of treatment with 4-methylcatechol (4MC), a known inducer of nerve growth factor, on peripheral nerve regeneration by analyzing cutaneous and muscular reinnervation in mice after sciatic nerve crush injury. At 3 months postinjury, the skin innervation index was significantly higher in the 4MC group than the control group (p=0.0002); there was also increased unmyelinated fiber density (p=0.0042) and unmyelinated fibers/Remak bundle (p = 0.001) in sural nerves, indicating unmyelinated nerve fiber regeneration. These changes were accompanied by increases of transcripts for nerve growth factor (p = 0.0026) and glial cell line-derived neurotrophic factor (p=0.03) in the 4MC group. In contrast, muscle innervation indices were similar in both groups and were higher than the skin innervation index (p < 0.0001). The regeneration of myelinated nerve fibers, as assessed by fiber density, diameter and g ratio analyses in sural nerves, and amplitudes of muscle action potential in sciatic nerves, was similar in both groups. Taken together, these data suggest that 4MC specifically promoted the regeneration of unmyelinated nerve fibers and reinnervation of the skin by increasing the expression of nerve growth factor and glial cell line-derived neurotrophic factor.

Following peripheral nerve injury, lidocaine application has been demonstrated to suppress injury discharges. However, there is very little information about the effects of lidocaine pre-treatment. The aim of the present study was to examine the effects of pre-treatment with lidocaine on injury discharges of the nerve, and neuropeptide Y (NPY) and c-Fos expression in the cuneate nucleus (CN) after median nerve transection (MNT). Rats received either saline or 1%, 5%, or 10% lidocaine applied topically to the median nerve before nerve transection. Electrophysiological recording was used to examine the changes in injury discharges of the nerve at post-injection, transection, pre- and post-electrical stimulation stages in the different groups. Sequential immunohistochemistry was also used to identify the number of NPY-like immunoreactive (NPY-LI) fibers and c-Fos-LI cells in the corresponding CN. An increasing frequency of injury discharges was observed at all stages in the pre-saline group, which were suppressed by lidocaine pre-treatment in a dose-dependent manner. Lidocaine pre-treatment also attenuated the number of injury-induced NPY-LI fibers and c-Fos-LI neurons within the CN in a dose-dependent manner. Furthermore, expression of c-Fos-LI neurons in the CN was significantly reduced by an NPY receptor antagonist, indicating that NPY modulated c-Fos expression following MNT. These data suggest that preventing injury discharges with lidocaine pre-treatment can effectively attenuate central sensitization following MNT.

This study sought to investigate the effects of injury-induced neuropeptide Y (NPY) on c-Fos expression in the cuneate neurons and neuropathic pain after median nerve injury. Four weeks after median nerve transection (MNT), the injured nerves stimulated at low intensity (0.1 mA) expressed significantly less NPY-like immunoreactive (NPY-LI) fibers in the cuneate nucleus (CN) than those stimulated at high intensities (1.0 mA and 10 mA). Conversely, a significantly higher number of c-Fos-LI cells were observed in the CN in rats stimulated with 0.1 mA compared to those stimulated with 1.0 mA or 10 mA. These results suggest that more NPY was released following low-intensity stimulation, and consequently fewer NPY-LI fibers and more c-Fos-LI cells were identified in the CN. Furthermore, the number of c-Fos-LI cells as well as the percentage of c-Fos-LI cuneothalamic projection neurons (CTNs) in the CN was markedly decreased after injection of NPY receptor antagonist along with retrograde tract-tracing method, indicating that NPY regulated c-Fos expression. In rats with median nerve chronic constriction injury (CCI), intracerebroventricular injection of NPY aggravated mechanical allodynia and low-intensity stimulus-evoked c-Fos expression, both of which were reversed by injection of NPY receptor antagonist. However, thermal hyperalgesia was not affected by injection of these two reagents. Taken together, these findings suggest that more NPY release, following low-intensity electrical stimulation of the injured nerve, significantly induces c-Fos expression in the CTNs, which possibly provide the ascending thalamic transmission of neuropathic pain signals.

This study applied the vestibular evoked myogenic potential (VEMP) test to guinea pigs coupled with electronic microscopic examination to determine whether VEMPs are dependent on type I or II hair cell activity of the saccular macula. An amount of 0.05 ml of gentamicin (40 mg/ml) was injected directly overlaying, but not through, the round window membrane of the left ear in guinea pigs.One week after surgery, auditory brainstem response test revealed normal responses in 12 animals (80%), and elevated thresholds in 3 animals (20%). The VEMP test using click stimulation showed absent responses in all 15 animals (100%). Another 6 gentamicin-treated animals underwent the VEMP test using galvanic stimulation and all 6 also displayed absent responses. Ultrathin sections of the saccular macula in the gentamicin-treated ears displayed morphologic alterations in type I or II hair cells, including shrinkage and/or vacuolization in the cytoplasm, increased electron density of the cytoplasm and nuclear chromatin, and cellular lucency. However, extrusion degeneration was rare and only present in type II hair cells. Quantitative analysis demonstrated that the histological density of intact type I hair cells was 1.1 +/- 1.2/4000 microm(2) in the gentamicin-treated ears, showing significantly less than that in control ears (4.5 +/- 1.8/4000 microm(2)). However, no significant difference was observed in the densities of intact type II hair cells and supporting cells between treated and control ears. Furthermore, the calyx terminals surrounding the damaged type I hair cells were swollen and disrupted, while the button afferents contacting the damaged type II hair cells were not obviously deformed. Based on the above results, we therefore conclude that VEMPs are heavily dependent on type I hair cell activity of the saccular macula in guinea pigs.

Objective: To investigate whether the saccule exhibits temporary or permanent functional loss resembling threshold shifts in auditory brainstem response (ABR) of guinea pigs following noise exposure., Design: Randomly bred guinea pigs were divided into 3 groups: A (short-term noise exposure, 30 minutes, n = 15), B (long-term noise exposure, 40 hours, n = 9), and C (no noise exposure, n = 5)., Setting: University hospital., Main Outcome Measures: All animals underwent vestibular-evoked myogenic potential (VEMP) and ABR tests. Chronological changes of VEMP and ABR responses following noise exposure were analyzed and compared. After audiovestibular function testing, animals were killed for morphological study with light and electron microscopy., Results: In group A, temporary VEMP loss and ABR threshold shifts recovered 2 and 4 days, respectively, after short-term noise exposure, with an interval of 2 days earlier in the recovery of VEMPs than that of ABR thresholds. In contrast, in group B, 78% and 83% of the ears exhibited permanent VEMP loss and ABR threshold shifts, respectively, 10 days following long-term noise exposure. In group C, all animals showed normal VEMPs and ABRs throughout the study period. Light and electron microscopic studies confirmed that loss of VEMPs correlated with saccular lesion., Conclusions: The saccule can exhibit temporary or permanent functional loss resembling hearing threshold shifts in guinea pigs following noise exposure. Recovery of VEMP precedes restoration of hearing threshold after damage from short-term noise exposure. Conversely, permanent VEMP loss after long-term noise exposure may reflect permanent hearing threshold shifts.

Previous studies have demonstrated that following complete median nerve transection (CMNT), neuropeptide Y-like immunoreactive (NPY-LI) fibers were dramatically increased and predominantly expressed in the ventral portion of the middle cuneate nucleus (CN), reaching maximum numbers at four weeks. Ultrastructurally, NPY-LI terminals made axodendritic synapses, but the postsynaptic elements are unknown. In the present study, using retrograde tract-tracing of wheat germ agglutinin conjugated with horseradish peroxidase (WGA-HRP) and NPY immunocytochemistry we examined the synaptic relationships between cuneothalamic projection neurons (CTNs) and NPY-LI terminals in the rat CN following CMNT. The injury-induced NPY-LI fibers were distributed throughout the rostrocaudal extent of the CN. Further, the greatest number of HRP-labeled CTNs was observed in the ventral portion of the middle CN. Ultrastructurally, the NPY-LI terminals made asymmetric axodendritic synaptic contact with the HRP-labeling CTN dendrites. These data suggest that injury-induced NPY may modulate the excitability of CTNs, and thus, play a role in the transmission of neuropathic sensation following median nerve injury.

In this study, we examined characteristics of the neuropeptide Y-like immunoreactive (NPY-LI) dorsal root ganglion (DRG) neurons after complete median nerve transection (CMNT). With fluorogold (FG) injection into normal median nerves, numerous FG-labeled DRG neurons were localized predominantly in the C6 and C7 DRGs, where the focal regions were examined after CMNT. With NPY immunohistochemistry, a few NPY-LI neurons were detected in the ipsilateral but not contralateral DRGs after FG injection into the nerve. As early as 3 days after CMNT a few NPY-LI neurons could be detected, reaching a maximum in the DRGs at 4 weeks, subsiding thereafter over 20 weeks. The NPY-LI DRG neurons were primarily medium-sized and large neurons. With FG injection into the transected median nerve, we found that approximately 99% of NPY-LI neurons were labeled for FG, suggesting that they were derived from the injured but not intact DRG neurons. Using double fluorescent dyes tracing, we detected that some of the injured DRG neurons were NPY-LI neurons that projected to the cuneate nucleus (CN). Following dorsal rhizotomy, our data indicated that after CMNT the induced NPY-LI fibers in the ipsilateral CN originated exclusively from the injured DRG neurons. Taken together, these findings suggest that injury-induced NPY-LI fibers in the CN may originate from the injured DRG neurons via the median primary afferent fibers, affect the excitability of cuneothalamic projection neurons (CTNs), and involve neuropathic sensation following CMNT.

Objectives: Although numerous studies have identified damage to the cochlear and vestibular end organs as the primary site of aminoglycoside-induced ototoxicity, the effect on the saccule remains poorly understood, possibly due to lack of monitoring saccular function in experimental animals. Therefore, this study applied three kinds of aminoglycosides into the tympanic space of guinea pigs to examine their toxic impact on the saccule by way of click-evoked myogenic potential test coupled with morphologic assessment., Design: Albino guinea pigs were treated with saline, gentamicin, tobramycin, or amikacin, with 10 animals assigned to each group. Each compound was injected directly overlying but not through the round window membrane on the left ear, with the right ear serving as a control. One week after injection, each animal underwent auditory brain stem response, caloric test, and click-evoked myogenic potential test. Animals were then killed for morphologic assessment through the use of light and electron microscopic examinations., Results: The animals treated with saline, gentamicin, tobramycin, or amikacin exhibited abnormal auditory brain stem response in 0%, 30%, 100%, and 30% of cases; abnormal caloric responses were found in 0%, 100%, 40%, and 40% of cases; absent click-evoked myogenic potentials were found in 0%, 100%, 30%, and 40% of cases, respectively. Gentamicin and other groups differed significantly in abnormal rates of caloric responses and click-evoked myogenic potentials. Morphologic study of the gentamicin-treated animals confirmed that the absence of click-evoked myogenic potential originated from the lesion in the saccular macula., Conclusions: Gentamicin represents the dominant susceptibility of aminoglycoside-induced vestibulotoxicity for eliminating both semicircular canal and saccular functions. This study further confirms the findings of human studies in which the caloric and vestibular evoked myogenic potentials responses were monitored to assess the abolition of vestibular function in patients treated with intratympanic gentamicin injection.

This study aimed to elucidate whether melatonin would exert beneficial effects on the neuronal functions of the nodose ganglion (NG) following acute hypoxic insult. The cytochrome oxidase (COX) and the nicotinamine adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry along with the nitric oxide synthase (NOS) immunofluorescence were used to examine the metabolic stage and nitric oxide production in nodose neurons respectively. Adult rats were injected intraperitoneally with melatonin at 5 or 100 mg/kg. Hypoxia was achieved by placing the rats into an altitude chamber (PO2 = 43 torr) for 4 hr. The results show that in normal untreated rats, nearly all and about 43% of the NG neurons displayed COX and NOS/NADPH-d reactivities with various staining intensities respectively. However, COX reactivity was drastically decreased while NOS/NADPH-d reactivity was significantly upregulated following hypoxia treatment. In melatonin pretreated rats, the hypoxia-induced reduction of COX reactivity was obviously prevented and the augmentation of NOS/NADPH-d reactivity was successfully suppressed. The deficit in the metabolic stage and the over-activation of NOS would contribute to the generation of oxidative stress. By effectively preventing the metabolic disruption, melatonin may have potential utility in therapeutic treatment of neuronal dysfunctions where oxidative stress is a participant.

We employed experimental degeneration, tract-tracing with wheatgerm agglutinin conjugated with horseradish peroxidase (WGA-HRP) and electron microscopy to explore the postganglionic sympathetic fibers in the hypoglossal nerve of hamsters. Quantitative results of normal untreated animals at the electron microscopic level showed the existence of unmyelinated fibers, which made up about 20% of the total fibers in the nerve, being more numerous on the left side. The nerve fibers were preferentially distributed at the periphery of the nerve. Following superior cervical ganglionectomy, most of the unmyelinated fibers underwent degenerative changes. Tract-tracing studies showed that some of the unmyelinated fibers were labeled by WGA-HRP injected into the superior cervical ganglion (SCG). It is suggested that the unmyelinated fibers represent the postganglionic sympathetic fibers originated from the SCG., (Copyright (c) 2005 S. Karger AG, Basel.)

We employed a double injury model (axotomy along with hypoxia) to determine how nerve injury and hypoxic insult would affect the expression of calcitonin gene-related peptide (CGRP) and choline acetyltransferase (ChAT) in the hypoglossal nucleus (HN) and nucleus ambiguus (NA). Adult rats were subjected to unilateral vagus and hypoglossal nerve transection, following which half of the animals were kept in an altitude chamber (PO2=380 Torr). The immunoexpression of CGRP and ChAT (CGRP-IR/ChAT-IR) were examined by quantitative immunohistochemistry at 3, 7, 14, 30 and 60 days post-axotomy. The results revealed that CGRP-IR in the HN was increased at 3 days but decreased to basal levels at 7 days following nerve injury. The decline was followed by a second rise in CGRP-IR at 30 days post-axotomy, followed again by a return to basal levels at 60 days. In the NA, CGRP-IR was up-regulated at 3 days and remained increased for up to 60 days after nerve injury. Animals treated with a double injury showed a greater CGRP-IR than normoxic group in both nuclei at all post-axtomized periods. In contrast to CGRP, ChAT-IR was markedly reduced in the HN and NA at 3 days reaching its nadir at 14 days following nerve injury. Hypoxic animals showed a stronger reduction of ChAT-IR in both nuclei at all post-axtomized periods. Results of cell counting showed that neuronal loss was somewhat obvious in hypoxic HN than that of normoxic ones. The present results suggest that up-regulation of CGRP-IR may exert its trophic effects while down-regulation of ChAT-IR may correlate with the poor neurotransmission within the injured neurons. It is speculated that the enhanced expression of CGRP-IR and the pronounced reduction of ChAT-IR in hypoxic rats may result from a drastic shift of intracellular metabolic pathways, which in turn could lead to more metabolic loading to the severely damaged neurons following the double insult.

Using median nerve injury and immunocytochemical methods, we examined the temporal changes in neuropeptide Y (NPY) expression in the cuneate nucleus (CN) in rats following median nerve transection. Under normal circumstances, neuropeptide Y-immunoreactive (NPY-IR) fibers was not detectable in the CN. A few NPY-IR fibers were observed in the ipsilateral CN 5 days after the median nerve transection, and peaked at 4 weeks. Thereafter, they were gradually returned to nearly control level after 16 weeks. Quantitative evaluation showed that the mean percentage of area occupied by NPY-IR fibers in entire and three subregions of the CN at 4 weeks were significantly higher than that at other post-operated time points, respectively. The present ultrastructural observations in the middle region of CN showed that the significantly increased NPY immunoreactivity was confined only in the myelinated axons and terminals but not detected in the dendrites, somata, and glial cells. The NPY-IR terminals made axodendritic synaptic contacts with unlabeled elements. The present results indicate that the time course of the increase of NPY immunoreactivity is similar to c-Fos expression as described in a previous study. It is speculated that the increased NPY in the CN after axotomy may affect the excitability of postsynaptic cuneate neurons, however, the functional interaction between NPY and c-Fos-IR neurons needs to be further studied.

Nitric oxide may serve as a neuronal messenger in the regulation of cardiorespiratory function via the N-methyl-D-aspartate (NMDA) receptor-mediated neuronal nitric oxide synthase (nNOS) activation. Since hypoxic stress would drastically influence the cardiorespiratory function, the present study aimed to examine if the expression of nNOS and NMDA receptor subunit 1 (NMDAR1) in the nodose ganglion (NG) would alter under different extents of hypoxia treatment. The nicotinamine adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, nNOS and NMDAR1 immunofluorescence were used to examine nNOS and NMDAR1 expression in the NG following exposing of adult rats in the altitude chamber (0.27 atm, PO(2)=43 torr) for 2 and 4 h. The present results showed that NADPH-d, nNOS and NMDAR1 reactivities were co-localized in the NG under normoxic and hypoxic environment. Quantitative evaluation revealed that about 43% of neurons in the NG showed positive response for NADPH-d/nNOS and NMDAR1 reactivities. However, in animals subjected to hypoxia, both the percentage and the staining intensity of NADPH-d/nNOS and NMDAR1 labeled neurons were drastically increased. The percentage of NADPH-d/nNOS and NMDAR1-immunoreactive neurons in the NG was raised to 68% as well as 77%, respectively, following 2 and 4 h of hypoxic exposure. The magnitude of up-regulation was positively correlated with the duration of hypoxic periods. No significant cell loss was observed under this experimental paradigm. These findings suggest that different extents of hypoxia might induce the higher expression of nNOS and NMDAR1 in the NG, which could contribute to the neuronal integration as responding to the different physiological demands under hypoxic stress.

In this study we investigate temporal changes in Fos expression in cuneate neurons after a high-threshold electrical stimulation of the transected median nerve in rats. Two hours after injury of the median nerve when given electrical stimulation, c-Fos-immunoreactive (c-Fos-IR) cells were barely detected in the ipsilateral cuneate nucleus (CN). A few c-Fos-IR cells, however, were observed in the ipsilateral CN at 5 days. A marked increase in c-Fos-IR cells was observed at 2, 3, and 4 weeks, but levels subsided thereafter. Labeled cells were totally diminished by 16 weeks. The statistical analysis showed that the mean density of c-Fos-IR cells throughout the CN at 4 weeks was significantly higher than at other post-surgical time points, except for 3 weeks. Furthermore, the mean density of c-Fos-IR cells in the middle region of the CN was markedly higher than in other areas of the nucleus. The mean density of c-Fos-IR cells in the middle region at 4 weeks (mean density = 35.9 +/- 3.0 cells/section) was considerably higher than at other time points. Combined retrograde Fluorogold (FG) labeling and c-Fos immunocytochemistry showed that throughout the CN about 60% (2270/3652) of the c-Fos-IR cells contained FG, confirming that they were cuneothalamic projection neurons (CTNs). Moreover, the percentage of double-labeled cells in the middle region at 2 weeks (78.9 +/- 0.6%) was significantly greater than at 3 (70.2 +/- 3.4%) and 4 weeks (66.0b +/- 1.4%) after injury. Although the mechanism leading to the vigorous c-Fos expression in the CTNs following the electrical stimulation of the transected median nerve remains unclear the hyperexcitable CTNs may transmit the neuropathic nociceptive sensation to the thalamus after the median nerve injury.

The genesis of the cuneothalamic neurons (CTNs) in the rat cuneate nucleus was determined by a double-labeling method using 5'-bromodeoxyuridine (BrdU), the thymidine analogue, and Fluoro-Gold (FG), a retrograde fluorescent tracer. BrdU-positive cells were observed in the cuneate nucleus in all rats receiving BrdU injection at embryonic days (E) E13--E16; none was detected in rats given BrdU injection at E12. At E13 and E14, BrdU-positive cells were randomly distributed. However, at E15, the number of BrdU-positive cells was clearly reduced and the majority of them was located at the dorsolateral or peripheral region of the nucleus. FG/BrdU double-labeling study showed the existence of BrdU-labeled CTNs when the mother rat received BrdU injection at E13 and E14, being more numerous at E13 in which the neurons were scattered throughout the nucleus. At E14, however, the majority of the BrdU-labeled CTNs were located superficially in the nucleus. Double-labeled cells were undetected in rats that had been exposed to BrdU at E15 and E16. Quantitative data showed that the majority (ca 70-80%) of the CTNs were generated at E13, and were markedly decreased at E14 (ca 4-6%). Using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry coupled with BrdU immunohistochemistry, we have shown the NADPH-d/BrdU double-labeled neurons in the nucleus between E13 and E15, with the majority of them occurring at E14, but absent at E16. The present results suggest that the CTNs are generated prior to the NO-containing neurons in the cuneate nucleus.

This study was aimed to determine whether axotomy coupled with hypoxia would exert a more profound effect on injury-induced neuronal nitric oxide synthase (NOS) expression. In this connection, the vagus and the hypoglossal nerves of adult rats were transected unilaterally in the same animal, and half of the operated animals were subjected to hypoxia treatment. Both the neuronal NOS immunohistochemistry and the nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry were used to assess the neuronal NOS expression. The present results have shown that the number of NADPH-d/NOS-positive [NADPH-d/NOS(1)] neurons in the hypoglossal nucleus (HN) peaked at 14 days after axotomy, while that in dorsal motor nucleus of vagus (DMN) and nucleus ambiguus (NA) was progressively increased up to 60 days. The up-regulation of NADPH-d/NOS in HN and DMN was more pronounced in hypoxic than in normoxic animals, a feature that was not evident in the NA. Quantitative analysis showed that the number of surviving motoneurons in normoxic animals was significantly higher than those subjected to hypoxia at 14 days postaxotomy in HN and at all postaxotomy time points in DMN. The difference may be attributed to their different functional components. Since O2 deprivation leads to poor cellular function, the stronger expression of NADPH-d/NOS and the more drastic neuronal loss following nerve transection in the hypoxic animals compared with the controls suggest that hypoxia plays an important role in peripheral neuropathies in which NO is implicated., (Copyright 2001 Academic Press.)

Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and nitric oxide synthase (NOS) immunohistochemistry have been used to characterize the nitric oxide (NO)-containing neurons in the rat cuneate nucleus. The present results showed that NADPH-d-positive/NOS-immunoreactive (-IR) neurons were distributed in the entire rostrocaudal extent of the nucleus. In the caudal region (approximately 1-2 mm caudal to the obex), NADPH-d/NOS-IR neurons were aggregated along the dorsal area of the nucleus notably in the lateral aspect. When traced rostrally, labeled neurons were progressively reduced and the cells were randomly distributed. The labeled neurons varied from round, ovoid to spindle-shaped with a mean profile area of about 140.1+/-1.7 microm(2) (n=720). They made up 7-10% of the neuronal population in the cuneate nucleus. By immunoelectron microscopy, the immunoreaction product was deposited throughout the cytoplasm extending from the soma to the proximal and distal dendrites. Results of NADPH-d staining paralleled that of NOS immunohistochemistry. Furthermore, NADPH-d reactivity and NOS-IR were colocalized in the same neurons following double labeling. Using NADPH-d histochemistry along with anti-gamma-aminobutyric acid (GABA) and -glycine postembedding immunolabeling for identification of GABA- and glycine-IR neurons, respectively, about 33% of the NADPH-d-positive neurons contained both GABA and glycine, 26% of them contained only glycine, while 41% of them showed neither GABA nor glycine labeling. Cuneothalamic neurons (CTNs) were identified by injecting the retrograde tracer Fluorogold (FG) into the ventrobasal complex of the thalamus. Numerous FG-labeled neurons were present in the contralateral cuneate nucleus, but none were reactive for NADPH-d. The present results suggest that approximately 60% of the NADPH-d/NOS-IR neurons in the cuneate nucleus are interneurons containing GABA and/or glycine.

This study was conducted to ascertain the possible expression of Fos-like immunoreactivity (Fos-LI) in the postsynaptic dorsal column (PSDC) neurons in response to noxious mechanical stimulation of the forepaw glabrous area of normal rats. For this purpose, Fos immunohistochemistry along with Fluoro-Gold (FG) retrograde tracing was utilized. After repeated noxious pinching of the forepaw glabrous area, there was a marked increase in number of Fos-LI neurons in the dorsal horn, including Rexed's laminae III and IV, at C5-T1 spinal cord segments ipsilateral to the stimulation. Between segments C5 and T1, about 40% of the Fos-LI neurons in laminae III and IV were distributed at segment C7. In the rats subjected to the noxious pinch coupled with FG injection into the right cuneate nucleus, PSDC neurons double labeled with Fos and FG were localized in the ipsilateral laminae III and IV extending from segment C5 to T1, with about 70% of them distributed at segments C6 and C7. At segment C6 or C7, double-labeled neurons made up about 10% of the PSDC neurons that projected their axons to the cuneate nucleus. Most of the double-labeled neurons appeared fusiform with their primary dendrites projected dorso-ventrally. The present results suggest that the morphologically distinct, subclasses of PSDC neurons in spinal laminae III and IV may contribute to the central transmission of mechanical nociceptive information through the dorsal column into the cuneate nucleus.

This study was aimed to clarify whether the primary afferent terminals (PATs), GABAergic terminals, and glutamatergic terminals made direct synaptic contacts with glycine-IR neurons in the cuneate nucleus of rats. In this connection, injection of the anterograde tracer WGA-HRP into brachial plexus, antiglycine preembedding immunoperoxidase, and anti-GABA, along with antiglutamate postembedding immunogold labeling, were used to identify the PATs, glycine-IR neurons, GABA-IR terminals, and glutamate-IR terminals, respectively. The present results showed that HRP-labeled PATs, immunoperoxidase-labeled glycine-IR terminals, immunogold-labeled GABA-IR, and glutamate-IR terminals made axodendritic synaptic contacts with immunoperoxidase-labeled glycine-IR neurons. The latter three presynaptic elements also formed axosomatic synapses with glycine-IR neurons. Statistical analysis has shown that the minimum diameter of the glycine-IR dendrites postsynaptic to the above-mentioned four presynaptic elements did not differ significantly. In addition, the synaptic ratio of the glutamate-IR terminals on the glycine-IR dendrites was higher than that of GABA-IR terminals. The synaptic ratio of the GABA-IR terminals on glycine-IR dendrite was in turn higher than that of the PATs and glycine-IR terminals. It is suggested that the PATs and glutamate-IR terminals on the glycine-IR neurons may be involved in subsequent postsynaptic inhibition for spatial precision of lateral inhibition. On the other hand, the GABA-IR and glycine-IR terminals which make synaptic contacts with the dendrites of glycine-IR neurons may provide a putative means for disinhibition or facilitation to maintain the baseline neuronal activity in the rat cuneate nucleus. The results of quantitative analysis suggest that glutamate act as the primary excitatory neurotransmitter, while GABA, when compared with glycine, may serve as a more powerful inhibitory neurotransmitter on glycine-IR neurons in the rat cuneate nucleus.

Previous studies have shown the existence of a sympathetic component in some cranial nerves including the hypoglossal nerve. In this study, the horseradish peroxidase (HRP) tract-tracing retrograde technique and experimental degeneration method were used to elucidate the possible neuroanatomical relationship between the superior cervical ganglion (SCG) and the hypoglossal nerve of hamsters. About 10% of the SCG principal neurons were HRP positive following the tracer application to the trunk of hypoglossal nerve. Most of the HRP-labelled neurons were multipolar and were randomly distributed in the ganglion. When HRP was injected into the medial branch of the hypoglossal nerve, some of the SCG neurons were labelled, but they were not detected when HRP was injected into the lateral branch. The present findings suggest that postganglionic sympathetic fibres from the SCG may travel along the hypoglossal nerve trunk via its medial branch to terminate in visceral targets such as the intralingual glands. By electron microscopy, the HRP reaction product was localised in the neuronal somata and numerous unmyelinated fibres in the SCG. In addition, HRP-labelled axon profiles considered to be the collateral branches of the principal neurons contained numerous clear round and a few dense core vesicles. Besides the above, some HRP-labelled small myelinated fibres, considered to be visceral afferents, were also present. Results of experimental degeneration following the severance of the hypoglossal nerve showed the presence of degenerating neuronal elements both in the hypoglossal nucleus and the SCG. This confirms that the hypoglossal nerve contains sympathetic component from the SCG which may be involved in regulation of the autonomic function of the tongue.

This study was aimed to investigate the possible involvement of neurons in the cuneate nucleus (CN) in the processing of A beta afferent inputs evoked by electrical stimulation of constricted median nerve in rats with behavioral signs of neuropathic pain. Immunohistochemical localization of Fos protein was used to examine the neuronal activation, and the combination of Fos immunohistochemistry with the retrograde labeling of Fluoro-Gold (FG) injected into the ventrobasal complex of the thalamus was used to characterize the activated neurons. Two weeks after unilateral median nerve constriction injury, the rats exhibited behavioral signs of neuropathic pain in the affected forepaws. In rats after nerve injury but without electrical stimulation, some Fos-like immunoreactive (Fos-LI) neurons were detected in the dorsal horn of the seventh cervical segment (C7) but none was found in the CN. Similar features were also noted when the stimulation of the intact median nerve served as an additional control. After A beta-fiber intensity stimulation of the previously constricted median nerve, an increase in number of Fos-LI neurons occurred in the medial half of the ipsilateral C7 dorsal horn as well as in the ipsilateral CN. In the latter, the Fos-LI neurons were located in the median nerve projection territory throughout the nucleus. Most of the Fos-LI neurons were distributed in the middle region of the CN, with about 78% of them emitting FG fluorescence indicating that they were cuneothalamic projection neurons. The results of this study suggest that the dorsal column-medial lemniscal system may contribute to the transmission and modulation of A beta-fiber mediated neuropathic pain signals.