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Aims: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, but its pathogenesis remains incompletely understood, particularly the involvements of central nervous system sensitization in colorectal visceral pain. Our study was to investigate whether the paraventricular thalamus (PVT) projected to the insular cortex (IC) to regulate colorectal visceral pain in neonatal colonic inflammation (NCI) mice and underlying mechanisms. Methods: We applied optogenetic, chemogenetic, or pharmacological approaches to manipulate the glutamatergicPVT‐IC pathway. Fiber photometry was used to assess neuronal activity. Electromyography activities in response to colorectal distension (CRD) were measured to evaluate the colorectal visceral pain. Results: NCI enhanced c‐Fos expression and calcium activity upon CRD in the ICGlu, and optogenetic manipulation of them altered colorectal visceral pain responses accordingly. Viral tracing indicated that the PVTGlu projected to the ICGlu. Optogenetic manipulation of PVTGlu changed colorectal visceral pain responses. Furthermore, selective optogenetic modulation of PVT projections in the IC influenced colorectal visceral pain, which was reversed by chemogenetic manipulation of downstream ICGlu. Conclusions: This study identified a novel PVT‐IC neural circuit playing a critical role in colorectal visceral pain in a mouse model of IBS. [ABSTRACT FROM AUTHOR]

Introduction: Neonatal stress disrupts brain development and increases the risk of neurological disorders later in life. However, the impact of neonatal stress on the development of the glymphatic system and susceptibility to Parkinson's disease (PD) remains largely unknown. Methods: Neonatal maternal deprivation (NMD) was performed on mice for 14 consecutive days to model chronic neonatal stress. Adeno‐associated virus expressing A53T‐α‐synuclein (α‐syn) was injected into the substantia nigra to establish PD model mice. Glymphatic activity was determined using in vivo magnetic resonance imaging, ex vivo fluorescence imaging and microplate assay. The transcription and expression of aquaporin‐4 (AQP4) and other molecules were evaluated by qPCR, western blotting, and immunofluorescence. Animal's responses to NMD and α‐syn overexpression were observed using behavioral tests. Results: Glymphatic activity was impaired in adult NMD mice. AQP4 polarization and platelet‐derived growth factor B (PDGF‐B) signaling were reduced in the frontal cortex and hippocampus of both young and adult NMD mice. Furthermore, exogenous α‐syn accumulation was increased and PD‐like symptoms were aggravated in adult NMD mice. Conclusion: The results demonstrated that NMD could disrupt the development of the glymphatic system through PDGF‐B signaling and increase the risk of PD later in life, indicating that alleviating neonatal stress could be beneficial in protecting the glymphatic system and reducing susceptibility to neurodegeneration. [ABSTRACT FROM AUTHOR]

Aims: Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive cognitive dysfunction and memory impairment. AD pathology involves protein acetylation. Previous studies have mainly focused on histone acetylation in AD, however, the roles of nonhistone acetylation in AD are less explored. Methods: The protein acetylation and expression levels were detected by western blotting and co‐immunoprecipitation. The stoichiometry of acetylation was measured by home‐made and site‐specific antibodies against acetylated‐CaM (Ac‐CaM) at K22, K95, and K116. Hippocampus‐dependent learning and memory were evaluated by using the Morris water maze, novel object recognition, and contextual fear conditioning tests. Results: We showed that calmodulin (CaM) acetylation is reduced in plasma of AD patients and mice. CaM acetylation and its target Ca2+/CaM‐dependent kinase II α (CaMKIIα) activity were severely impaired in AD mouse brain. The stoichiometry showed that Ac‐K22, K95‐CaM acetylation were decreased in AD patients and mice. Moreover, we screened and identified that lysine deacetylase 9 (HDAC9) was the main deacetylase for CaM. In addition, HDAC9 inhibition increased CaM acetylation and CaMKIIα activity, and hippocampus‐dependent memory in AD mice. Conclusions: HDAC9‐mediated CaM deacetylation induces memory impairment in AD, HDAC9, or CaM acetylation may become potential therapeutic targets for AD. [ABSTRACT FROM AUTHOR]

Aims: Gastric hypersensitivity (GHS) is a characteristic pathogenesis of functional dyspepsia (FD). DNA methyltransferase 1 (DNMT1) and acid‐sensing ion channel 1 (ASIC1) are associated with GHS induced by prenatal maternal stress (PMS). The aim of this study was to investigate the mechanism of DNMT1 mediating the analgesic effect of folic acid (FA) on PMS‐induced GHS. Methods: GHS was quantified by electromyogram recordings. The expression of DNMT1, DNMT3a, DNMT3b, and ASIC1 were detected by western blot, RT‐PCR, and double‐immunofluorescence. Neuronal excitability and proton‐elicited currents of dorsal root ganglion (DRG) neurons were determined by whole‐cell patch clamp recordings. Results: The expression of DNMT1, but not DNMT3a or DNMT3b, was decreased in DRGs of PMS rats. FA alleviated PMS‐induced GHS and hyperexcitability of DRG neurons. FA also increased DNMT1 and decreased ASIC1 expression and sensitivity. Intrathecal injection of DNMT1 inhibitor DC‐517 attenuated the effect of FA on GHS alleviation and ASIC1 downregulation. Overexpression of DNMT1 with lentivirus not only rescued ASIC1 upregulation and hypersensitivity, but also alleviated GHS and hyperexcitability of DRG neurons induced by PMS. Conclusions: These results indicate that increased DNMT1 contributes to the analgesic effect of FA on PMS‐induced GHS by reducing ASIC1 expression and sensitivity. [ABSTRACT FROM AUTHOR]

Aims: Visceral hypersensitivity is a major clinic symptom in patients with irritable bowel syndrome (IBS). Anterior cingulate cortex (ACC) is involved in processing the information of pain. Both G protein‐coupled receptor kinase 6 (GRK6) and P2Y purinoceptor 6 (P2Y6) are associated with neuroinflammation and pathological pain. The aim of this study was to investigate the interaction between GRK6 and P2Y6 in ACC in the development of visceral hypersensitivity of adult offspring rats with prenatal maternal stress (PMS). Methods: Visceral hypersensitivity was quantified by abdominal withdrawal reflex threshold to colorectal distension (CRD). The expression and cellular distribution of GRK6 and P2Y6 were determined by Western blotting, qPCR, and fluorescence immunohistochemistry. Co‐immunoprecipitation was used to evaluate the interaction between GRK6 and P2Y6. Results: The mRNA and protein levels of GRK6 were significantly decreased in ACC of PMS rats. The injection of GRK6 overexpression virus significantly attenuated visceral hypersensitivity of PMS rats. P2Y6's mRNA level, protein level, and ratio of membrane protein over total protein expression was markedly increased in PMS rats. P2Y6 antagonist MRS2578 microinjection reversed visceral hypersensitivity of PMS rats. GRK6 overexpression significantly reduced P2Y6's expression in membrane proteins and P2Y6's ratio of membrane protein over total protein expression. Conclusions: These results indicate that decreased GRK6 leads to the accumulation of P2Y6 at neuron membrane in ACC, thereby contributing to visceral hypersensitivity of PMS rats. [ABSTRACT FROM AUTHOR]

Background: Inflammatory pain is a severe clinical problem that affects the quality of life in patients. However, the currently available treatments for inflammatory pain have limited effect and even causes severe side effects. The aim of this study was to investigate the roles of miRNA‐107 and glutamate transporter 1 (GLT‐1) in the inflammatory pain of rats induced by complete Freund's adjuvant (CFA). Methods: Paw withdrawal threshold (PWT) of rats was measured by von Frey Filaments. The expressions of miRNA‐107 and GLT‐1 in the lumbar spinal dorsal horn (L4‐L6) were measured with real‐time quantitative PCR and western blotting analysis. Fluorescent in situ hybridization and fluorescent‐immunohistochemistry were employed to detect the expression of miRNA‐107, GLT‐1 and co‐location of miRNA‐107 with GLT‐1. Results: Injection of CFA significantly reduced PWT of rats. The miRNA‐107 expression level was obviously up‐regulated while the GLT‐1 expression level was decreased in the spinal dorsal horn of CFA rats. miRNA‐107 and GLT‐1 were co‐expressed in the same cells of the spinal dorsal horn in CFA rats. Ceftriaxone, a selective activator of GLT‐1, obviously increased the PWT of CFA rats. Furthermore, antagomir of miRNA‐107 reversed the down‐regulation of GLT‐1 and alleviated CFA‐induced mechanical allodynia of CFA rats. Conclusions: These results suggest that an increase of miR‐107 contributes to inflammatory pain through downregulating GLT‐1 expression, implying a promising strategy for pain therapy. Significance: The currently available treatments for inflammatory pain has limited effect even causes severe side effects. MiRNAs may have important diagnostic and therapeutic potential in inflammatory pain. In present study, we show a potential spinal mechanism of allodynia in rat inflammatory pain model induced by CFA. Increased miR‐107 contribute to inflammatory pain by targeting and downregulating GLT‐1 expression, implying a promising strategy for inflammatory pain. [ABSTRACT FROM AUTHOR]

Aims: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disease characterized by abdominal pain. Our recent study has shown that the acid‐sensitive ion channel 1 (ASIC1) in dorsal root ganglion (DRG) is involved in stomachache of adult offspring rats subjected with prenatal maternal stress (PMS). MiR‐485 is predicted to target the expression of ASIC1. The aim of the present study was designed to determine whether miR‐485/ASIC1 signaling participates in enterodynia in the spinal dorsal horn of adult offspring rats with PMS. Methods: Enterodynia was measured by colorectal distension (CRD). Western blotting, qPCR, and in situ hybridization were performed to detect the expression of ASICs and related miRNAs. Spinal synaptic transmission was also recorded by patch clamping. Results: PMS offspring rats showed that spinal ASIC1 protein expression and synaptic transmission were significantly enhanced. Administration of ASICs antagonist amiloride suppressed the synaptic transmission and enterodynia. Besides, PMS induced a significant reduction in the expression of miR‐485. Upregulating the expression markedly attenuated enterodynia, reversed the increase in ASIC1 protein and synaptic transmission. Furthermore, ASIC1 and miR‐485 were co‐expressed in NeuN‐positive spinal dorsal horn neurons. Conclusions: Overall, these data suggested that miR‐485 participated in enterodynia in PMS offspring, which is likely mediated by the enhanced ASIC1 activities. [ABSTRACT FROM AUTHOR]

Aims: Painful diabetic neuropathy (PDN) is a refractory complication of diabetes. The study aimed to investigate the role of α‐lipoic acid (ALA) on the regulation of transient receptor potential vanilloid‐1 (TRPV1) in dorsal root ganglion (DRG) neurons of rats with diabetes. Methods: Whole‐cell patch‐clamp recordings were employed to measure neuronal excitability in DiI‐labeled DRG neurons of control and streptozotocin (STZ)‐induced diabetic rats. Western blotting and immunofluorescence assays were used to determine the expression and location of NF‐κBp65 and TRPV1. Results: STZ‐induced hindpaw pain hypersensitivity and neuronal excitability in L4‐6 DRG neurons were attenuated by intraperitoneal injection with ALA once a day lasted for one week. TRPV1 expression was enhanced in L4‐6 DRGs of diabetic rats compared with age‐matched control rats, which was also suppressed by ALA treatment. In addition, TRPV1 and p65 colocated in the same DRG neurons. The expression of p65 was upregulated in L4‐6 DRGs of diabetic rats. Inhibition of p65 signaling using recombinant lentiviral vectors designated as LV‐NF‐κBp65 siRNA remarkably suppressed TRPV1 expression. Finally, p65 expression was downregulated by ALA treatment. Conclusion: Our findings demonstrated that ALA may alleviate neuropathic pain in diabetes by regulating TRPV1 expression via affecting NF‐κB. [ABSTRACT FROM AUTHOR]

Aims Insular cortex ( IC) is involved in processing the information of pain. The aim of this study was to investigate roles and mechanisms of P2X7 receptors (P2X7Rs) in IC in development of visceral hypersensitivity of adult rats with neonatal maternal deprivation ( NMD). Methods Visceral hypersensitivity was quantified by abdominal withdrawal reflex threshold to colorectal distension ( CRD). Expression of P2X7Rs was determined by qPCR and Western blot. Synaptic transmission in IC was recorded by patch-clamp recording. Results The expression of P2X7Rs and glutamatergic neurotransmission in IC was significantly increased in NMD rats when compared with age-matched controls. Application of Bz ATP (P2X7R agonist) enhanced the frequency of spontaneous excitatory postsynaptic currents ( sEPSC) and miniature excitatory postsynaptic currents ( mEPSC) in IC slices of control rats. Application of BBG (P2X7R antagonist) suppressed the frequencies of sEPSC and mEPSC in IC slices of NMD rats. Microinjection of Bz ATP into right IC significantly decreased CRD threshold in control rats while microinjection of BBG or A438079 into right IC greatly increased CRD threshold in NMD rats. Conclusion Data suggested that the enhanced activities of P2X7Rs in IC, likely through a presynaptic mechanism, contributed to visceral hypersensitivity of adult rats with NMD. [ABSTRACT FROM AUTHOR]

Aims To investigate whether electroacupuncture ( EA) produced analgesic effect and whether nuclear factor kappa B ( NF-κ B) and cystathionine β synthase ( CBS) involved in EA-mediated analgesia in painful diabetic neuropathy in rats. Methods Diabetes was induced by an intraperitoneal injection of streptozotocin ( STZ) in adult female rats. Mechanical pain threshold was measured by von Frey filaments. EA was applied at acupoint Zu- San- Li ( ST-36) in both hindlimbs. Western blot analysis was employed to detect changes in protein levels of NF-κB and CBS in spinal dorsal root ganglion ( DRGs). Results Mechanical allodynia was developed 2 weeks after STZ injection and lasted for another 4 weeks. STZ injection significantly enhanced expression of p65 and CBS in lumbar L4-6 DRGs when compared with age-matched controls. EA markedly attenuated mechanical allodynia. Importantly, EA treatment remarkably inhibited p65 and CBS expression in DRGs. Additionally, intrathecal injection of the p65 antagonist pyrrolidine dithiocarbamate attenuated mechanical allodynia and markedly inhibited CBS expression in DRGs in STZ rats. Conclusions These data indicate that EA produced an analgesic effect, which might be mediated at least in a part by inhibition of NF-κB signaling pathway in primary sensory neurons in rats with diabetes. [ABSTRACT FROM AUTHOR]

Aims: To investigate whether electroacupuncture (EA) produced analgesic effect and whether nuclear factor kappa B (NF-κB) and cystathionine β synthase (CBS) involved in EA-mediated analgesia in painful diabetic neuropathy in rats., Methods: Diabetes was induced by an intraperitoneal injection of streptozotocin (STZ) in adult female rats. Mechanical pain threshold was measured by von Frey filaments. EA was applied at acupoint Zu-San-Li (ST-36) in both hindlimbs. Western blot analysis was employed to detect changes in protein levels of NF-κB and CBS in spinal dorsal root ganglion (DRGs)., Results: Mechanical allodynia was developed 2 weeks after STZ injection and lasted for another 4 weeks. STZ injection significantly enhanced expression of p65 and CBS in lumbar L4-6 DRGs when compared with age-matched controls. EA markedly attenuated mechanical allodynia. Importantly, EA treatment remarkably inhibited p65 and CBS expression in DRGs. Additionally, intrathecal injection of the p65 antagonist pyrrolidine dithiocarbamate attenuated mechanical allodynia and markedly inhibited CBS expression in DRGs in STZ rats., Conclusions: These data indicate that EA produced an analgesic effect, which might be mediated at least in a part by inhibition of NF-κB signaling pathway in primary sensory neurons in rats with diabetes., (© 2012 Blackwell Publishing Ltd.)