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Alzheimer's disease (AD) is one of the most common causes of dementia, accounting for more than 60% of all cases. It is a neurodegenerative disease in which symptoms such as a decline in memory, thinking, learning, and organizing skills develop gradually over many years and eventually become more severe. To date, there is no effective treatment for the cause of Alzheimer's disease, and the existing pharmacological options primarily help manage symptoms. Treatment is mainly based on acetylcholinesterase (AChE) inhibitors such as donepezil, rivastigmine, and galantamine, which exhibit numerous adverse cardiovascular and gastrointestinal effects due to excessive stimulation of peripheral cholinergic activity involving muscarinic receptors. Therefore, in addition to the obvious drugs that act on the cause of the disease, new drugs based on AChE inhibition that show the fewest side effects are needed. One potential drug could be a new compound under study, tetrahydroacridine derivative (CHDA), which showed significant potential to inhibit the AChE enzyme in previous in vitro studies. The present study shows that while having very potent AChE inhibitory properties, CHDA is a compound with low toxicity to nerve cell culture and living organisms. In addition, it exhibits dissociative activity against amyloid β fibrils, which is extremely important for applications in Alzheimer's disease therapy. [ABSTRACT FROM AUTHOR]

Introduction: Glass coverslips are used as a substrate since Harrison's initial nerve cell culture experiments in 1910. In 1974, the first study of brain cells seeded onto polylysine (PL) coated substrate was published. Usually, neurons adhere quickly to PL coating. However, maintaining cortical neurons in culture on PL coating for a prolonged time is challenging. Methods: A collaborative study between chemical engineers and neurobiologists was conducted to find a simple method to enhance neuronal maturation on poly-D-lysine (PDL). In this work, a simple protocol to coat PDL efficiently on coverslips is presented, characterized, and compared to a conventional adsorption method. We studied the adhesion and maturation of primary cortical neurons with various morphological and functional approaches, including phase contrast microscopy, immunocytochemistry, scanning electron microscopy, patch clamp recordings, and calcium imaging. Results: We observed that several parameters of neuronal maturation are influenced by the substrate: neurons develop more dense and extended networks and synaptic activity is enhanced, when seeded on covalently bound PDL compared to adsorbed PDL. Discussion: Hence, we established reproducible and optimal conditions enhancing maturation of primary cortical neurons in vitro. Our method allows higher reliability and yield of results and could also be profitable for laboratories using PL with other cell types. [ABSTRACT FROM AUTHOR]

Although the neurotoxicity of ZnO nanoparticles (NPs) has been evaluated in animal and nerve cell culture models, these models cannot accurately mimic human brains. Three-dimensional (3D) brain organoids based on human-induced pluripotent stem cells have been developed to study the human brains, but this model has rarely been used to evaluate NP neurotoxicity. We used 3D brain organoids that express cortical layer proteins to investigate the mechanisms of ZnO NP-induced neurotoxicity. Cytotoxicity caused by high levels of ZnO NPs (64 μg/mL) correlated with high intracellular Zn ion levels but not superoxide levels. Exposure to a non-cytotoxic concentration of ZnO NPs (16 μg/mL) increased the autophagy-marker proteins LC3B-II/I but decreased p62 accumulation, whereas a cytotoxic concentration of ZnO NPs (64 μg/mL) decreased LC3B-II/I proteins but did not affect p62 accumulation. Fluorescence micro-optical sectioning tomography revealed that 64 μg/mL ZnO NPs led to decreases in LC3B proteins that were more obvious at the outer layers of the organoids, which were directly exposed to the ZnO NPs. In addition to reducing LC3B proteins in the outer layers, ZnO NPs increased the number of micronuclei in the outer layers but not the inner layers (where LC3B proteins were still expressed). Adding the autophagy flux inhibitor bafilomycin A1 to ZnO NPs increased cytotoxicity and intracellular Zn ion levels, but adding the autophagy inducer rapamycin only slightly decreased cellular Zn ion levels. We conclude that high concentrations of ZnO NPs are cytotoxic to 3D brain organoids via defective autophagy and intracellular accumulation of Zn ions. [ABSTRACT FROM AUTHOR]

Previous studies using monotypic nerve cell cultures have shown that nanoparticles induced neurotoxic effects on nerve cells. Interactions between neurons and Schwann cells may protect against the neurotoxicity of nanoparticles. In this study, we developed a co-culture model consisting of immortalized rat dorsal root ganglion (DRG) neurons and rat Schwann cells and employed it to investigate our hypothesis that co-culturing DRG neurons with Schwann cells imparts protection on them against neurotoxicity induced by silver or gold nanoparticles. Our results indicated that neurons survived better in co-cultures when they were exposed to these nanoparticles at the higher concentrations compared to when they were exposed to these nanoparticles at the same concentrations in monotypic cultures. Synapsin I expression was increased in DRG neurons when they were co-cultured with Schwann cells and treated with or without nanoparticles. Glial fibrillary acidic protein (GFAP) expression was increased in Schwann cells when they were co-cultured with DRG neurons and treated with nanoparticles. Furthermore, we found co-culturing with Schwann cells stimulated neurofilament polymerization in DRG neurons and produced the morphological differentiation. Silver nanoparticles induced morphological disorganization in monotypic cultures. However, there were more cells displaying normal morphology in co-cultures than in monotypic cultures. All of these results suggested that co-culturing DRG neurons with Schwann cells imparted some protection on them against neurotoxicity induced by silver or gold nanoparticles, and altering the expression of neurofilament-L, synapsin I, and GFAP could account for the phenomenon of protection in co-cultures. [ABSTRACT FROM AUTHOR]

To investigate the regulatory effect of miR-1298 on hypoxic-ischemic nerve injury by cell culture in vitro. Firstly, the modeling effect of oxygen glucose deprivation/reoxygenation (OGD/R) of rat PC-12 cells was determined by cell activity detection and lactate dehydrogenase (LDH) cytotoxicity. At the same time, the expression difference of miR-1298 was detected by real-time fluorescence quantitative PCR (RT-qPCR). The miR-1298mimic, mimic NC, miR-1298 inhibitor and inhibitor NC were transfected into rat PC-12 cell line in vitro. The transfection efficiency of miR, mimic NC, inhibitor and inhibitor NC was detected. After OGD/R treatment, the cells were divided into control group, OGD/R group, mimicgroup, mimicNC group, inhibitor group and inhibitor NC group. The apoptosis of PC-12 cells in each group was detected by flow cytometry, and the expression of PC-12 apoptosis related protein B lymphoma-2 gene (BCL-2) and Bcl-2 associated X protein (BAX) were detected by Western blot. After OGD/R treatment, the survival rate of PC12 cells decreased significantly compared with the control group, and the leakage rate of LDH increased significantly (all P<0.05). The relative expression of miR-1298 in model cells was significantly lower than that in control group (P<0.05). 24 hours after transfection, the relative expression of miR-1298 in mimic group cells was significantly higher than that in mimicNC group ( P<0.05). The cells apoptosis rate in mimic group was lower than that in mimicNC group, while cells apoptosis rate in inhibitor group was higher than that in inhibitor NC group (all P<0.05). The expression of BCL-2 in mimic group was higher than that in mimicNC group, while the expression of BAX decreased. Compared with the inhibitorNC group, the expression of BCL-2 decreased, while the expression of BAX increased, and the differences were statistically significant (all P<0.05). miR-1298 alleviates the injury of OGD/R in PC-12 cells by inhibiting apoptosis. [ABSTRACT FROM AUTHOR]

Fabrication of scaffolds for nerve regeneration is one of the most challenging topics in regenerative medicine at the moment, which is also interlinked with the development of biocompatible substrates for cells growth. This work is targeted towards the development of green biomaterial composite scaffolds for nerve cell culture applications. Hybrid scaffolds of hydroxyethyl cellulose/glycine (HEC/Gly) composite doped with different concentrations of green ruthenium oxide (RuO 2) were synthesized and characterized via a combination of different techniques. X-rays diffraction (XRD) and differential scanning calorimetry (DSC) analyses showed a crystalline nature for all the samples with noticeable decrease in the peak intensity of the fabricated scaffolds as compared to that for pure glycine. Fourier transform infrared spectroscopy (FTIR) tests revealed an increase in the vibrational bands of the synthesized RuO 2 containing scaffolds which are related to the functional groups of the natural plant extract (Aspalathuslinearis) used for RuO 2 nanoparticles (NPs) synthesis. Scanning electron microscopy (SEM) results revealed a 3D porous structure of the scaffolds with variant features attributed to the concentration of RuO 2 NPs in the scaffold. The compressive test results recorded an enhancement in mechanical properties of the fabricated scaffolds (up to 8.55 MPa), proportionally correlated to increasing the RuO 2 NPs concentration in HEC/Gly composite scaffold. Our biocompatibility tests revealed that the composite scaffolds doped with 1 and 2 ml of RuO 2 demonstrated the highest proliferation percentages (152.2 and 135.6%) compared to control. Finally, the SEM analyses confirmed the impressive cells attachments and differentiation onto the scaffold surfaces as evidenced by the presence of many neuron-like cells with apparent cell bodies and possessing few short neurite-like processes. The presence of RuO 2 and glycine was due to their extraordinary biocompatibility due to their cytoprotective and regenerative effects. Therefore, we conclude that these scaffolds are promising for accommodation and growth of neural-like cells. [ABSTRACT FROM AUTHOR]

Although they have been regarded, in the past, as passive support cells, many experimental data have shown that glial cells play a critical role in the development and functioning of the nervous system. Despite the advances that have been made in understanding astrocytes' role in the nervous system's development and function, our knowledge of their interactions with other cells is still limited, albeit neurons are dependent on the trophic support provided by astrocytes release. Materials and Methods. The use of the McCarthy and de Vellis methods for isolating glial cells has been regarded as an essential tool for studying their function. This study aims to evaluate the effects of ethanol and deferoxamine on primary rat glial cell cultures and try to explain, as far as possible, the relevance of such effects for patients with chronic alcoholism and traumatic spinal cord injuries. Discussion. Because glial cells are very important in the functioning of the central nervous system and experiments cannot be performed on human primary nerve cell cultures, we performed an experiment on glial cells harvested from the newborn rat, analyzing the dynamics of IL-6 and TNF alpha on models of suffering in spinal cord injury (hypoxia and thermally stress). Conclusion. Inhibition of TNF alpha synthesis was more important at 7 days posttraumatic in cells with prolonged ethanolic exposure, even if protein levels of IL-6 were elevated (under similar experimental conditions). Thus, we can say that long-term exposure to ethanol of nerve cells can ensure a favorable evolution of medical recovery (by increasing TNF alpha), even if the inflammatory process remains active (shown by elevated IL-6 values). [ABSTRACT FROM AUTHOR]

Collagen provides a promising environment for 3D nerve cell culture; however, the function of perfusion culture and cell-growth guidance is difficult to integrate into such an environment to promote cell growth. In this paper, we develop a bio-inspired design method for constructing a perfusion culture platform for guided nerve cell growth and differentiation in collagen. Based on the anatomical structure of peripheral neural tissue, a biomimetic porous structure (BPS) is fabricated by two-photon polymerization of IP-Visio. The micro-capillary effect is then utilized to facilitate the self-assembly of cell encapsulated collagen into the BPS. 3D perfusion culture can be rapidly implemented by inserting the cell-filled BPS into a pipette tip connected with syringe pumps. Furthermore, we investigate the nerve cell behavior in the BPS. 7-channel aligned cellular structures surrounded with a Schwann cell layer can be stably formed after a long-time perfusion culture. Differentiation of PC12 cells and mouse neural stem cells shows 3D neurite outgrowth alignment and elongation in collagen. The calcium activities of differentiated PC12 cells are visualized for confirming the preliminary formation of cell function. These results demonstrate that the proposed bio-inspired 3D cell culture platform with the advantages of miniaturization, structure complexity and perfusion has great potential for future application in the study of nerve regeneration and drug screening. [ABSTRACT FROM AUTHOR]

Background: Xylazole (Xyl) is a veterinary anesthetic that is structurally and functionally similar to xylazine. However, the effects of Xyl in vitro remain unknown. Objectives: This study aimed to investigate the anesthetic mechanism of Xyl using fetal rat nerve cells treated with Xyl. Methods: Fetal rat nerve cells cultured for seven days were treated with 10, 20, 30, and 40 μg/mL Xyl for 0, 5, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min. Variations of amino acid neurotransmitters (AANTs), Nitric oxide-Cyclic GMP (NO-cGMP) signaling pathway, and ATPase were evaluated. Results: Xyl decreased the levels of cGMP and NO in nerve cells. Furthermore, Xyl affected the AANT content and Na+-K+-ATPase and Ca2+-Mg2+-ATPase activity in nerve cells. These findings suggested that Xyl inhibited the NO-cGMP signaling pathway in nerve cells in vitro. Conclusions: This study provided new evidence that the anesthetic and analgesic effects of Xyl are related to the inhibition of the NO-cGMP signaling pathway. [ABSTRACT FROM AUTHOR]

We have previously developed ammonium sulphate gradient loaded liposomes to encapsulate dibucaine. Thus, the purpose of this study was to evaluate the pre-clinical safety and effectiveness of this novel ionic liposomal formulation of dibucaine (DBC), as described in previous work. Effectiveness was evaluated in vivo on Wistar rats (n = 8) that received plain DBC or liposomal DBC (DBCLUV). Control empty liposomes (without DBC) or saline were also used as control. Sciatic nerve block was performed using the formulations or controls (0.4 mL). A hindpaw incision-based postoperative pain model was used to evaluate mechanical hypersensitivity with von Frey filaments. To verify antiinflamatory activity protein levels of TNF-α, IL-1β, substance P and CGRP were measured by ELISA in the hindpaw tissue after 1 and 6 hours of the incision. To corroborate drug safety, sciatic nerve Schwann cell cultures were treated with the aforementioned formulations and assessed for cell viability (MTT assay) and death (flow cytometry assay). Histopathology of the tissues surrounding the sciatic nerve region was also assessed 2 and 7 days after treatment. All animals presented post incisional hypersensitivity and DBCLUV showed longer analgesic effect (p < 0.001). DBCLUV reduced TNF-α and CGRP levels (p < 0.05). Histopathological evaluation showed greater inflammatory reaction after the administration of control liposomes when compared to DBC (p < 0.05). There was no difference in Schwann cell viability and death between plain and encapsulated DBC. DBCLUV was safe and enhanced anaesthesia duration due to slow release of dibucaine from ammonium sulphate gradient loaded liposomes. [ABSTRACT FROM AUTHOR]

Axonal injury and stress have long been thought to play a pathogenic role in a variety of neurodegenerative diseases. However, a model for studying single-cell axonal injury in mammalian cells and the processes of repair has not been established. The purpose of this study was to examine the response of neuronal growth cones to laser-induced axonal damage in cultures of embryonic rat hippocampal neurons and induced pluripotent stem cell (iPSC) derived human neurons. A 532-nm pulsed [Formula: see text] picosecond laser was focused to a diffraction limited spot at a precise location on an axon using a laser energy/power that did not rupture the cell membrane (subaxotomy). Subsequent time series images were taken to follow axonal recovery and growth cone dynamics. After laser subaxotomy, axons thinned at the damage site and initiated a dynamic cytoskeletal remodeling process to restore axonal thickness. The growth cone was observed to play a role in the repair process in both hippocampal and iPSC-derived neurons. Immunofluorescence staining confirmed structural tubulin damage and revealed initial phases of actin-based cytoskeletal remodeling at the damage site. The results of this study indicate that there is a repeatable and cross-species repair response of axons and growth cones after laser-induced damage.

Hypothesis: Nowadays, the use of scaffolds in tissue engineering to repair and regenerate human lesions, including nervous injuries has been widely considered. Also, nanofibrous scaffolds due to their structural similarity with the extracellular matrix (ECM) in the body are found to be suitable substrates for cell growth. Therefore, the main focus of the present work is on the production of conductive nanofibrous scaffolds for neural cell culture and their electrical stimulation performance.Methods: Two biocompatible polymers including polycaprolactone (PCL) and poly(lactic-co-glycolicacid) (PLGA) were used as main materials, and polyaniline (PANI) was applied as a conductive polymer to create conductivity in the substrates. After determination and optimization of the electrospinning process factors, 4 types of nanofibrous scaffolds with 4 levels of conductive polymer (0%, 1%, 10% and 18%) were prepared. To investigate the effect of scaffolds' conductivity and electrical stimulation on the nerve cells behavior, a plate with steel electrodes was designed to apply electrical field to the scaffolds during cell culture experiments.Findings: SEM, Dino-Lite digital microscopy, Potentiostat-Galvanostat and 3-(4,5-dimethylthiazed-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to study the properties of scaffolds including hydrophilicity, conductivity, fiber diameter and the results of cell culture. By investigation of the physical properties of the scaffolds it was shown that increasing the amount of PANI in scaffolds causes significant drop in the fiber diameter and hydrophilicity. In cell culture experiment, shape and proliferation of nerve cells were studied. MTT assay and SEM images showed that electrical stimulation, proportional to the amount of polyaniline, enhanced neurite outgrowth compared to the scaffolds that were not subjected to electrical stimulation. Furthermore, proliferation of cells on conductive scaffolds (by 10% v/w of PANI) increased and subsequently the cell proliferation decreased with increasing conductive polymer content due to its toxicity.

Cellular models are a very important research tool in modern neurobiology. The presented review of Russian and international literature summarizes the main data of experimental studies, conducted over the past 15 years, aimed at modeling in vitro acute and chronic forms of cerebral pathology in order to reveal the mechanisms of their pathogenesis and to develop approaches to their pharmacological correction. The results of modeling of ischemic neurodestructive processes, epilepsy, Parkinson's disease, Alzheimer's disease and Huntington's disease, obtained using modern cellular research methods, such as cell cultivation in a multielectrode system and technology of induced pluripotent stem cells, are presented. A number of key concepts related to this problem are illustrated with the data obtained by the author and his laboratory. In conclusion, the short-term goals and prospects of in vitro studies of pathogenic mechanisms of neurological diseases and of the search for new neuroprotectors are formulated.

Neurite outgrowth involves reciprocal signaling interactions between tumor cells and nerves where invading tumor cells have acquired the ability to respond to pro-invasive signals within the nerve environment. Neurite outgrowth could serve as a mechanism leading to invasion of cancer cells into the nerve sheath and subsequent metastasis. Snail transcription factor can promote migration and invasion of prostate cancer cells. We hypothesized that prostate cancer cell interaction with nerve cells will be mediated by Snail expression within prostate cancer cells. For this study we utilized various prostate cancer cell lines: C4-2 non-silencing (NS, control); C4-2 Snail shRNA, (stable Snail knockdown); LNCaP Neo (empty vector control) and LNCaP Snail (stably over-expressing Snail). Cancer cell adhesion and migration towards nerve cells (snF96.2 or NS20Y) was examined by co-culture assays. Conditioned media (CM) collected from C4-2 cells was cultured with nerve cells (PC-12 or NS20Y) for 48 h followed by qualitative or quantitative neurite outgrowth assay. Our results showed that cancer cells expressing high levels of Snail (LNCaP Snail/C4-2 NS) displayed significantly higher migration adherence to nerve cells, compared to cells with lower levels of Snail (LNCaP Neo/C4-2 Snail shRNA). Additionally, LNCaP Snail or C4-2 NS (Snail-high) CM led to a higher neurite outgrowth compared to the LNCaP Neo or C4-2 Snail shRNA (Snail-low). In conclusion, Snail promotes migration and adhesion to nerve cells, as well as neurite outgrowth via secretion of soluble factors. Therefore, targeting cancer cell interaction with nerves may contribute to halting prostate cancer progression/metastasis. • Prostate cancer cells expressing Snail transcription factor migrate towards nerve cells. • Snail transcription factor promotes adhesion of prostate cancer cells to nerve cells. • Conditioned media from Snail-expressing prostate cancer cells promotes neurite outgrowth. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous studies have found that the culture supernatant of the olfactory ensheathing cells is capable of promoting axonal regeneration and functional recovery after spinal cord injury, but there is a lack of research in the field of peripheral nerve. OBJECTIVE: To investigate whether olfactory ensheathing cell culture supernatant is beneficial for nerve repair after peripheral nerve injury. METHODS: Olfactory ensheathing cells were isolated and purified, to prepare the supernatant. The olfactory ensheathing cell culture supernatant was applied to the dorsal root ganglion tissue block in vitro to observe the axon growth of the dorsal root ganglion. The olfactory ensheathing cell culture supernatant was applied to a rat sciatic nerve defect model in vivo to examine its effect on axonal regeneration and myelinization of the injured nerve. RESULTS AND CONCLUSION: The purity of olfactory ensheathing cells was (94.4±3.1)%. Compared with the blank control and low dose olfactory ensheathing cell culture groups, the average length of five longest axons in dorsal root ganglion tissue mass in the high dose olfactory ensheathing cells culture group was significantly increased (P < 0.05). Immunofluorescence showed that the regenerated nerve penetrated through the defect area and the regenerated nerve was arranged orderly in the olfactory ensheathing cell culture and the autologous nerve groups, which was significantly superior to that in the blank control group. Transmission electron microscope observed that the number of regenerated nerve axons and the thickness of myelin sheath in the olfactory ensheathing cell culture group were significantly higher than those in the blank control group (P < 0.05). These results indicate that the supernatant of the olfactory ensheathing cells can promote axonal regeneration after peripheral nerve injury and the myelination of the regenerated axons, which provides a new olfactory ensheathing cells-based acellular therapy for peripheral nerve injury. [ABSTRACT FROM AUTHOR]

Dissociated cultures from many species have been important tools for exploring factors that regulate structure and function of central neuronal synapses. We have previously shown that cells harvested from brains of late stage Drosophila pupae can regenerate their processes in vitro. Electrophysiological recordings demonstrate the formation of functional synaptic connections as early as 3 days in vitro (DIV), but no information about synapse structure is available. Here, we report that antibodies against pre-synaptic proteins Synapsin and Bruchpilot result in punctate staining of regenerating neurites. Puncta density increases as neuritic plexuses develop over the first 4 DIV. Electron microscopy reveals that closely apposed neurites can form chemical synapses with both pre- and postsynaptic specializations characteristic of many inter-neuronal synapses in the adult brain. Chemical synapses in culture are restricted to neuritic processes and some neurite pairs form reciprocal synapses. GABAergic synapses have a significantly higher percentage of clear core versus granular vesicles than non-GABA synapses. Gap junction profiles, some adjacent to chemical synapses, suggest that neurons in culture can form purely electrical as well as mixed synapses, as they do in the brain. However, unlike adult brain, gap junctions in culture form between neuronal somata as well as neurites, suggesting soma ensheathing glia, largely absent in culture, regulate gap junction location in vivo. Thus pupal brain cultures, which support formation of interneuronal synapses with structural features similar to synapses in adult brain, are a useful model system for identifying intrinsic and extrinsic regulators of central synapse structure as well as function.

Agrin mediates motor neuron-induced differentiation of the postsynaptic apparatus of the neuromuscular junction but its function in brain remains unknown. Here we report that expression of c-fos, induced by activation of nicotinic or glutamatergic receptors, was significantly lower in cortical neurons cultured from agrin-deficient mutant mouse embryos compared to wildtype. Agrin-deficient neurons also exhibited increased resistance to excitotoxic injury. Treatment with recombinant agrin restored glutamate-induced c-fos expression and excitotoxicity of the agrin-deficient neurons to near wild-type levels, confirming the agrin dependence of the phenotype. The observation that c-fos induction by activation of voltage-gated Ca2+ channels is also reduced in agrin-deficient neurons raises the possibility that agrin may play a wider role by regulating responses to Ca(2+)-mediated signals. Consistent with the decline in response of cultured mutant neurons to glutamate, decreases in kainic acid-induced seizure and mortality were observed in adult agrin heterozygous mice. Together, these data demonstrate that agrin plays an important role in defining neuronal responses to excitatory neurotransmitters both in vitro and in vivo.

Damage to the nervous system, in particular spinal cord injuries, is a burden for the patient and is usually the cause of irreversible disability. The progress observed in the last decade in the fields of biology, biomaterial engineering and neurosurgery has created new treatment solutions while preventing further neurodegenerative processes. The most important research is focused on the implementation of polymer structures in clinical practice, especially chitosan hydrogels, which are the scaffolds for regenerating axons. This article presents a new generation of biomaterials that have the ability to gel in response to temperature changes; they are intended for injectable scaffolds for nerve cell cultures. Two types of hydrogels were prepared based on chitosan lactate and chitosan chloride using uridine 5'-monophosphate disodium salt. The structure of the systems was observed under a scanning electron microscope and examined using Fourier transform infrared spectroscopy. In addition, thermal properties were tested using differential scanning calorimetry. [ABSTRACT FROM AUTHOR]

Neuregulin 1 (NRG1) regulates the expression of the nicotinic acetylcholine receptor (nAChR) and is suggested to promote the survival and maintenance of the enteric nervous system (ENS), since deficiency of its corresponding receptor complex ErbB2/ErbB3 leads to postnatal colonic aganglionosis. As diverticular disease (DD) is associated with intestinal hypoganglionosis, the NRG1-ErbB2/ErbB3 system and the nAChR were studied in patients with DD and controls. Samples of tunica muscularis of the sigmoid colon from patients with DD (n = 8) and controls (n = 11) were assessed for mRNA expression of NRG1, ErbB2, and ErbB3 and the nAChR subunits α3, α5, α7, β2, and β4. Site-specific gene expression levels of the NRG1-ErbB2/3 system were determined in myenteric ganglia harvested by laser microdissection (LMD). Localization studies were performed by immunohistochemistry for the NRG1-ErbB2/3 system and nAChR subunit β4. Rat enteric nerve cell cultures were stimulated with NRG1 or glial-cell line derived neurotrophic factor (GDNF) for 6 days and mRNA expression of the aforementioned nAchR was measured. NRG1, ErbB3, and nAChR subunit β4 expression was significantly down-regulated in both the tunica muscularis and myenteric ganglia of patients with DD compared to controls, whereas mRNA expression of ErbB3 and nAChR subunits β2, α3, α5, and α7 remained unaltered. NRG1, ErbB3, and nAChR subunit β4 immunoreactive signals were reduced in neuronal somata and the neuropil of myenteric ganglia from patients with DD compared to control. nAChR subunit β4 exhibited also weaker immunoreactive signals in the tunica muscularis of patients with DD. NRG1 treatment but not GDNF treatment of enteric nerve cell cultures significantly enhanced mRNA expression of nAchR β4. The down-regulation of NRG1 and ErbB3 in myenteric ganglia of patients with DD supports the hypothesis that intestinal hypoganglionosis observed in DD may be attributed to a lack of neurotrophic factors. Regulation of nAChR subunit β4 by NRG1 and decreased nAChR β4 in patients with DD provide evidence that a lack of NRG1 may affect the composition of enteric neurotransmitter receptor subunits thus contributing to the intestinal motility disorders previously reported in DD. [ABSTRACT FROM AUTHOR]

Charcot-Marie-Tooth (CMT) disease is a peripheral neuropathy associated with gene duplication and point mutations in the peripheral myelin protein 22 (PMP22) gene. However, the role of PMP22 in Schwann cell physiology and the mechanisms by which PMP22 mutations cause CMT are not well-understood. On the basis of homology between PMP22 and proteins associated with modulation of ion channels, we hypothesized that PMP22 alters ion channel activity. Using whole-cell electrophysiology, we show here that heterologous PMP22 expression increases the amplitude of currents similar to those ascribed to store-operated calcium (SOC) channels, particularly those involving transient receptor canonical channel 1 (TrpC1). These channels help replenish Ca2+ in the endoplasmic reticulum (ER) following stimulus-induced depletion. Currents with similar properties were recorded in WT but not pmp22-/- mouse Schwann cells. Heterologous expression of the CMT-associated PMP22_L16P variant, which fails to reach the plasma membrane and localizes to the ER, led to larger currents than WT PMP22. Similarly, Schwann cells isolated from Trembler J (TrJ; PMP22_L16P) mice had larger currents than WT littermates. Calcium imaging in live nerves and cultured Schwann cells revealed elevated intracellular Ca2+ in TrJ mice compared with WT. Moreover, we found that PMP22 co-immunoprecipitated with stromal interaction molecule 1 (STIM1), the Ca2+ sensor SOC channel subunit in the ER. These results suggest that in the ER, PMP22 interacts with STIM1 and increases Ca2+ influx through SOC channels. Excess or mutant PMP22 in the ER may elevate intracellular Ca2+ levels, which could contribute to CMT pathology. [ABSTRACT FROM AUTHOR]

We developed a complex in vitro model of ischemic damage. Analysis of hippocampal cell viability in primary cultures after modeling of various stress factors revealed the features of action of the main pathological factors of ischemia. Neurotrophic factors BDNF and GDNF produced pronounced neuroprotective effect during modeling both the complex ischemic damage and its individual pathophysiological components. Neurotrophic factor GDNF produced the most pronounced protective effect. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract In addiction, an individual's ability to inhibit drug seeking and drug taking is thought to reflect a pathological strengthening of drug-seeking behaviors or impairments in the capacity to control maladaptive behavior. These processes are not mutually exclusive and reflect drug-induced modifications within prefrontal cortical and nucleus accumbens circuits, however unlike psychostimulants such as cocaine, far less is known about the temporal, anatomical, and cellular dynamics of these changes. We discuss what is known regarding opioid-induced adaptations in intrinsic membrane physiology and pre-/postsynaptic neurotransmission in principle pyramidal and medium spiny neurons in the medial prefrontal cortex and nucleus accumbens from electrophysiological studies and explore how circuit specific adaptations may contribute to unique facets of opioid addiction. [ABSTRACT FROM AUTHOR]

Este artículo examina la distintividad explicativa de los modelos de optimización del cableado en neurociencia. Los modelos de optimización del cableado se proponen representar los rasgos organizativos de los sistemas neuronales y cerebrales como soluciones óptimas (o casi óptimas) a problemas de optimización del cableado. Afirmo que los modelos de optimización proporcionan explicaciones de diseño. En particular, estos modelos soportan intervenciones ideales sobre las variables de decisión de un problema de diseño relevante, y evalúan el impacto de esas intervenciones sobre la viabilidad del sistema en cuestión. [ABSTRACT FROM AUTHOR]

Highlights • Statistical parameters of uncertain outcomes (expected value, risk, probability) are coded by single neurons in the orbitofrontal cortex. • Orbitofrontal neurons code an integrated expected value signal. • These parameters are predominantly coded by separate subpopulations of orbitofrontal neurons. Abstract Uncertain reward outcomes are characterised by statistical parameters that capture the numerical values of the underlying probability distributions of reward values, including the expected value, risk (variance) and probability. Here we show coding of an integrated expected value signal by single orbitofrontal neurons in response to visual cues predicting uncertain rewards. Separate subpopulations of orbitofrontal neurons predominantly code the prediction of one statistical parameter with few neurons showing combined coding. These signals are likely combined with subjective value signals to inform learning and decision making under conditions of uncertainty. [ABSTRACT FROM AUTHOR]

Abstract Glutamate excitotoxicity plays a crucial role in the pathogenesis behind the development and progression of several neurodegenerative diseases. The study aimed to investigate the neuroprotective activity of Gallic acid (GA) against glutamate-induced neurotoxicity in primary rat cortex neurons (RCN). Treated the RCNs with GA 25 & 50 μg/ml for 2 h and later treated the cells with 100 μM glutamate (GLU) and incubated for 24 h at 37 °C. The results demonstrated that, the GA improved the antioxidant profile in the cortex neurons and inhibited the production of the proinflammatory cytokine. GA also maintained the Ca2+ homeostasis, IGF-1 expression, and protected the neurons from glutamate-induced neuronal toxicity. The neuroprotective activity of GA has further confirmed from the results of N-acetylaspartate and expression of microtubule-associated protein-2 expression. The reports suggest that, GA is significantly attenuated the glutamate-induced neurotoxicity and protected neurons from various chemical events that are involved in the pathogenesis of neurotoxicity. Highlights • Glutamate excitotoxicity is a major pathogenesis behind the development and progression of neurodegenerative diseases. • Glutamate-induced neurotoxicity in RCN is mediated through the formation of free radicles and proinflammatory cytokine. • Glutamate treatment also caused an alteration in Ca2+ homeostasis and decline in IGF-1 level. • Observed a down-regulation of MAP-2 expression and NAA concentration in glutamate treated rat cortex neurons. • Treatment with GA improved the antioxidant status in neurons and inhibited proinflammatory cytokine production. • GA also maintained the Ca2+ homeostasis, IGF-1 expression, and protected neurons from glutamate-induced neuronal toxicity. [ABSTRACT FROM AUTHOR]

The nucleus accumbens (NAc) contains multiple subpopulations of medium spiny neurons (MSNs). One subpopulation expresses D1-type dopamine receptors, another expresses D2-type receptors, and a third expresses both. The relative roles in NAc of D1 neurons versus D2 neurons in appetitive motivation were assessed here. Specifically, we asked whether D1-Cre mice would instrumentally seek optogenetic self-stimulation specifically targeted at D1 MSNs in NAc, and similarly if D2-Cre mice would self-stimulate D2 neurons in NAc. Mice were implanted with Cre-targeted channelrhodopsin (ChR2) virus and optic fibers in NAc. Subsequently, mice could earn brief NAc laser illuminations by actively touching a metal spout in one task, or by going to a particular location in a separate task. Results indicated that D1 neuronal excitation in NAc supported intense self-stimulation in both tasks. D1-Cre mice earned hundreds to thousands of spout-touches per half-hour session, and also sought out locations that delivered NAc laser to excite D1 MSNs. By comparison, D2 ChR2 mice showed lower but still positive levels of self-stimulation in the spout-touch task, earning dozens to hundreds of NAc laser illuminations. However, in the location task, D2 mice failed to show positive self-stimulation. If anything, a few D2 individuals gradually avoided the laser location. Brain-wide measures indicated that D1 and D2 stimulations in NAc recruited heavily overlapping patterns of Fos activation in distant limbic structures. These results confirm that excitation of D1 MSNs in NAc supports strong incentive motivation to self-stimulate. They also suggest that excitation of D2 neurons in NAc supports self-stimulation under some conditions, but fails under others and possibly may even shift to negative avoidance. [ABSTRACT FROM AUTHOR]

When objects transform into different views, some properties are maintained, such as whether the edges are convex or concave, and these non-accidental properties are likely to be important in view-invariant object recognition. The metric properties, such as the degree of curvature, may change with different views, and are less likely to be useful in object recognition. It is shown that in a model of invariant visual object recognition in the ventral visual stream, VisNet, non-accidental properties are encoded much more than metric properties by neurons. Moreover, it is shown how with the temporal trace rule training in VisNet, non-accidental properties of objects become encoded by neurons, and how metric properties are treated invariantly. We also show how VisNet can generalize between different objects if they have the same non-accidental property, because the metric properties are likely to overlap. VisNet is a 4-layer unsupervised model of visual object recognition trained by competitive learning that utilizes a temporal trace learning rule to implement the learning of invariance using views that occur close together in time. A second crucial property of this model of object recognition is, when neurons in the level corresponding to the inferior temporal visual cortex respond selectively to objects, whether neurons in the intermediate layers can respond to combinations of features that may be parts of two or more objects. In an investigation using the four sides of a square presented in every possible combination, it was shown that even though different layer 4 neurons are tuned to encode each feature or feature combination orthogonally, neurons in the intermediate layers can respond to features or feature combinations present is several objects. This property is an important part of the way in which high capacity can be achieved in the four-layer ventral visual cortical pathway. These findings concerning non-accidental properties and the use of neurons in intermediate layers of the hierarchy help to emphasise fundamental underlying principles of the computations that may be implemented in the ventral cortical visual stream used in object recognition. [ABSTRACT FROM AUTHOR]

The end-points of a moving bar (intrinsic terminators) contain unambiguous information that can be used to extract the bar’s correct direction of motion, regardless of the orientation of the bar. However, extrinsic terminators, formed at the intersection of two overlapping bars, can result in motion signals with conflicting directions compared to those of the intrinsic terminators. Using a computational model, we propose that interactions between form and motion information may assist neurons in the motion-specific regions of primate cortex to differentiate intrinsic from extrinsic terminators. The motion processing model has two stages. The first stage is a model of V1 complex neurons, including end-stopped neurons. The resulting first stage motion signals are transmitted to the second stage, which is a model of MT neurons. In the proposed model, MT neurons additionally receive form information from neurons in V1 that are not orientation or direction selective but respond strongly to the contrast of the stimulus. These neurons have polarity-dependent center–surround receptive fields, as found in layer 4 of V1 in primates. As the inhibitory surrounds of these neurons are less activated at the intrinsic terminators, the signals generated by the end-points of the objects are stronger than the signals from the extrinsic terminators, which are inhibited by strong suppression from the surround. Therefore, the excitatory inputs received by integration MT neurons from center–surround V1 neurons enhance the unambiguous motion signals at the intrinsic terminators, which therefore dominate over the local motion signals generated at X-junctions. The results show that, despite the inability of V1 end-stopped neurons to distinguish between the two different types of terminators, center–surround V1 neurons provide the capacity for the second stage of the model to preferentially respond to the intrinsic terminators and, therefore, predict the true directions of the crossing bars. [ABSTRACT FROM AUTHOR]

Objectives. To study the neuroprotective properties of lithium ascorbate (LA) in in vivo and in vitro stress models. Materials and methods. Neurocytological and behavioral studies were run in models of stress in nerve cell cultures and experimental animals. Results. LA was shown to have a marked neuroprotective effect in conditions of glutamate-induced cytotoxicity in vitro and an adaptogenic effect on induction of stress in vivo. Conclusions. The results obtained here demonstrated that LA has high neuroprotective potential in stress induced in vivo and in vitro. [ABSTRACT FROM AUTHOR]

Pathological synchronisation of beta frequency (12–35 Hz) oscillations between the subthalamic nucleus (STN) and cerebral cortex is thought to contribute to motor impairment in Parkinson's disease (PD). For this cortico-subthalamic oscillatory drive to be mechanistically important, it must influence the firing of STN neurons and, consequently, their downstream targets. Here, we examined the dynamics of synchronisation between STN LFPs and units with multiple cortical areas, measured using frontal ECoG, midline EEG and lateral EEG, during rest and movement. STN neurons lagged cortical signals recorded over midline (over premotor cortices) and frontal (over prefrontal cortices) with stable time delays, consistent with strong corticosubthalamic drive, and many neurons maintained these dynamics during movement. In contrast, most STN neurons desynchronised from lateral EEG signals (over primary motor cortices) during movement and those that did not had altered phase relations to the cortical signals. The strength of synchronisation between STN units and midline EEG in the high beta range (25–35 Hz) correlated positively with the severity of akinetic-rigid motor symptoms across patients. Together, these results suggest that sustained synchronisation of STN neurons to premotor-cortical beta oscillations play an important role in disrupting the normal coding of movement in PD. [ABSTRACT FROM AUTHOR]

Cell–cell communication plays a central role in the guidance of migrating neuronal precursor cells during the development of the cerebral cortex. Endocannabinoids (eCBs) have previously been shown to be one of the central factors regulating neuronal migration. In this study the effects of eCBs on different parameters, expected to affect embryonic cortical neuronal motility have been analyzed in neurosphere-derived neuroblasts using time-lapse microscopy. Increased endogenous production of the endocannabinoid 2-arachidonyl glycerol (2-AG) causes bursts of neuroblast motility. The neuroblasts move longer distances and show a low frequency of turning, and the number of neuron–neuron contacts are reduced. Similar changes occur interfering with the function of the metabotropic glutamate receptor 5 (mGluR5) or its transducer canonical transient receptor potential channel 3 (TRPC3) or the neuregulin receptor ErbB4. Blocking of 2-AG production reverses these effects. The data suggest that eCB-regulated neuronal motility is controlled by mGluR5/TRPC3 activity possibly via NRG/ErbB4 signaling. [ABSTRACT FROM AUTHOR]

Background Insights into human brain diseases may emerge from tissue obtained after operations on patients. However techniques requiring transduction of transgenes carried by viral vectors cannot be applied to acute human tissue. New method We show that organotypic culture techniques can be used to maintain tissue from patients with three different neurological syndromes for several weeks in vitro. Optimized viral vector techniques and promoters for transgene expression are described. Results Region-specific differences in neuronal form, firing pattern and organization as well as pathological activities were maintained over 40–50 days in culture. Both adeno-associated virus and lentivirus based vectors were persistently expressed from ∼10 days after application, providing 30–40 days to exploit genetically expressed constructs. Different promoters, including hSyn, e/hSyn, CMV and CaMKII, provided cell-type specific transgene expression. The Ca probe GCaMP let us explore epileptogenic synchrony and a FRET-based probe was used to follow activity of the kinase mTORC1. Comparison with existing methods The use of a defined culture medium, with low concentrations of amino acids and no growth factors, permitted organotypic culture of tissue from humans aged 3–62 years. Epileptic activity was maintained and excitability changed relatively little until ∼6 weeks in culture. Conclusions Characteristic morphology and region-specific neuronal activities are maintained in organotypic culture of tissue from patients diagnosed with mesial temporal lobe epilepsy, cortical dysplasia and cortical glioblastoma. Viral vector techniques permit expression of probes for long-term measurements of multi-cellular activity and intra-cellular signaling. [ABSTRACT FROM AUTHOR]

Background: Bilirubin-induced neurological dysfunction (BIND), a severe complication of extreme neonatal hyperbilirubinemia, could develop into permanent neurodevelopmental impairments. Several studies have demonstrated that inflammation and nerve cell death play important roles in bilirubin-induced neurotoxicity; however, the underlying mechanism remains unidentified.Methods: The present study was intended to investigate whether pyroptosis, a highly inflammatory form of programmed cell death, participated in the bilirubin-mediated toxicity on cultured rat cortical astrocytes. Further, VX-765, a potent and selective competitive drug, was used to inhibit the activation of caspase-1. The effects of VX-765 on astrocytes treated with bilirubin, including the cell viability, morphological changes of the cell membrane and nucleus, and the production of pro-inflammation cytokines, were observed.Results: Stimulation of the astrocytes with unconjugated bilirubin (UCB) at the conditions mimicking those of jaundiced newborns significantly increased the activation of caspase-1. Further, caspase-1 activation was inhibited by treatment with VX-765. Compared with UCB-treated astrocytes, the relative cell viability of VX-765-pretreated astrocytes was improved; meanwhile, the formation of plasma membrane pores was prevented, as measured by lactate dehydrogenase release, trypan blue staining, and ethidium bromide (EtBr) uptake. Moreover, DNA fragmentation was partly attenuated and the release of IL-1β and IL-18 was apparently decreased.Conclusion: Pyroptosis is involved in the process of UCB-induced rat cortical astrocytes' injury in vitro and may be the missing link of cell death and inflammatory response exacerbating UCB-related neurotoxicity. More importantly, the depression of caspase-1 activation, the core link of pyroptosis, attenuated UCB-induced cellular dysfunction and cytokine release, which might shed light on a new therapeutic approach to BIND. [ABSTRACT FROM AUTHOR]

During the development of the central nervous system (CNS), only motor axons project into peripheral nerves. Little is known about the cellular and molecular mechanisms that control the development of a boundary at the CNS surface and prevent CNS neuron emigration from the neural tube. It has previously been shown that a subset of spinal cord commissural axons abnormally invades sensory nerves in Ntn1 hypomorphic embryos and Dcc knockouts. However, whether netrin 1 also plays a similar role in the brain is unknown. In the hindbrain, precerebellar neurons migrate tangentially under the pial surface, and their ventral migration is guided by netrin 1. Here, we show that pontine neurons and inferior olivary neurons, two types of precerebellar neurons, are not confined to the CNS in Ntn1 and Dcc mutant mice, but that they invade the trigeminal, auditory and vagus nerves. Using a Ntn1 conditional knockout, we show that netrin 1, which is released at the pial surface by ventricular zone progenitors is responsible for the CNS confinement of precerebellar neurons. We propose, that netrin 1 distribution sculpts the CNS boundary by keeping CNS neurons in netrin 1-rich domains. [ABSTRACT FROM AUTHOR]

The diversification of neuronal subtypes during corticogenesis is fundamental to the establishment of the complex cortical structure. Although subtype specification has been assumed to occur in neural progenitor cells, increasing evidence has begun to reveal the plasticity of subtype determination in immature neurons. Here, we summarize recent findings regarding the regulation of subtype specification during later periods of neuronal differentiation, such as the post-mitotic and post-migratory stages. We also discuss thalamocortical axons as an extra-cortical cue that provides information on the subtype determination of immature cortical neurons. [ABSTRACT FROM AUTHOR]

Layer 2/3 (L2/3) excitatory neurons in the neocortex make major contributions to corticocortical connections and therefore function to integrate information across cortical areas and hemispheres. Recent evidence suggests that excitatory neurons in L2/3 can have different properties. Sparse evidence from previous studies suggests that L2 neurons located at the border between L1 and L2 (referred to as L2 marginal neurons, L2MNs), have a morphology distinct from a typical pyramidal neuron. However, whether the membrane properties and input/output properties of L2MNs are different from those of typical pyramidal neurons in L2/3 is unknown. Here we addressed these questions in a slice preparation of mouse temporal cortex. We found that L2MNs were homogeneous in intrinsic membrane properties but appeared diverse in morphology. In agreement with previous studies, L2MNs either had oblique apical dendrites or had no obvious apical dendrites. The tufts of both apical and basal dendrites of these neurons invaded L1 extensively. All L2MNs showed a regular firing pattern with moderate adaptation. Compared with typical L2/3 pyramidal neurons that showed regular spiking (RS) activity (neurons), L2MNs showed a higher firing rate, larger sag ratio, and higher input resistance. No difference in the amplitude of excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs, respectively), evoked by stimulation of L1, was found between the two types of neurons, but the IPSPs in L2MNs had a slower time course than those in L2/3 RS cells. In paired recordings, unitary EPSPs showed no significant differences between synapses formed by L2MNs and those formed by L2/3 RS neurons. However, short-term synaptic depression (STSD) examined with a L2MN as the presynaptic neuron was greater when another L2MN was the postsynaptic neuron than when a L2/3 RS neuron was the postsynaptic neuron. The distinct morphological features of L2MNs found here have developmental implications, and the differences in electrophysiological properties between L2MNs and other L2/3 pyramidal neurons suggest that they play different functional roles in cortical networks. [ABSTRACT FROM AUTHOR]

Proper communication among neurons depends on an appropriately formed dendritic arbor, and thus, aberrant changes to the arbor are implicated in many pathologies, ranging from cognitive disorders to neurodegenerative diseases. Due to the importance of dendritic shape to neuronal network function, the morphology of dendrites is tightly controlled and is influenced by both intrinsic and extrinsic factors. In this work, we examine how brain-derived neurotrophic factor (BDNF), one of the most well-studied extrinsic regulators of dendritic branching, affects the arbor when it is applied locally via microbeads to cultures of hippocampal neurons. We found that local application of BDNF increases both proximal and distal branching in a time-dependent manner and that local BDNF application attenuates pruning of dendrites that occurs with neuronal maturation. Additionally, we examined whether cytosolic PSD-95 interactor (cypin), an intrinsic regulator of dendritic branching, plays a role in these changes and found strong evidence for the involvement of cypin in BDNF-promoted increases in dendrites after 24 but not 48 h of application. This current study extends our previous work in which we found that bath application of BDNF for 72 h, but not shorter times, increases proximal dendrite branching and that this increase occurs through transcriptional regulation of cypin. Moreover, this current work illustrates how dendritic branching is regulated differently by the same growth factor depending on its spatial localization, suggesting a novel pathway for modulation of dendritic branching locally. [ABSTRACT FROM AUTHOR]

Graphical abstract To develop disease-modifying therapies for Alzheimer's disease (AD), an understanding of the pathways that lead to synaptic damage and neuronal cell death is required. The ME7 prion mouse model shares hallmarks of human neurodegenerative diseases and has a well-defined disease progression that can be monitored non-invasively through changes in behaviour. In addition, a strong involvement of neuroinflammation in ME7 disease progression and systemic inflammatory challenge has provided rationale to study and target cytokines in human AD patients. Furthermore, susceptibility of the model to acute cognitive deficits generated a model of delirium has supported human dementia studies. Thus, the ME7 prion model provides a translatable model of neurodegeneration and neuroinflammation that could provide validation of potential treatments against the inflammatory response during neurodegeneration. [ABSTRACT FROM AUTHOR]

Ageing is accompanied by decreased overall fitness and performance. Studying brain ageing in humans is challenging due to limited or no access to healthy tissue, limited opportunities for interventions and complicated confounding factors. The generation of mouse ageing models with uniform genetic backgrounds significantly contributed to understanding (brain) ageing at the molecular level. Research has focused on evolutionarily conserved mechanisms or pathways that control ageing to facilitate data extrapolation to humans. Understanding how these pathways contribute to pathological ageing may help us understand human central nervous system (CNS) ageing and assist in the development of possible therapeutic targets. In this review, we focus on the functional consequences and pathological changes in the CNS of ageing mouse models. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Neural cell cultures can be used to model different aspects of spinal cord injury. • In vitro models range from individual cell types through to complex co-cultures. • Simple cultures may be easier to scale up to high throughput, however lack the cell-cell cross talk and 3D architecture found in the central nervous system. There are great challenges involved in identifying potential therapies for the repair of spinal cord injury (SCI). It is well accepted that not one, but a combination of therapeutic strategies will be required to effectively repair the damage. However, identifying novel therapeutics is hindered by the lack of reliable methods available that facilitate high throughput screening of numerous compounds. While the use of animals provides an important means for testing new therapies, in vivo models of SCI can be time consuming and require the use of large cohorts of animals. In this review, we have focused on three aspects of repair following SCI (1) neurite outgrowth, (2) glial scar and (3) remyelination. No in vitro model encapsulates all the features of SCI and we discuss the limitations and virtues of the various cultures, which range from individual cell-types through to complex co-cultures. We discuss how these cultures can be used as a moderate throughput screen to identify novel therapeutics for CNS repair before being verified in animal models. [ABSTRACT FROM AUTHOR]

A proteinic fraction from the skin secretion of Trachycephalus typhonius showed antinociceptive activity in mice when tested by the Hot Plate method. This fraction was purified, and a peptide named Tt7 with a molecular mass of 6,509.7 Da was identified. The primary structure of Tt7 was elucidated. Comparing Tt7 with the structure of other analgesic peptides, it exhibits a strong relationship with the family of anntoxins, which are peptides isolated from the skin secretions of Asian frogs of the genus Hyla, whereas T. typhonius is located only in the Americas. Tt7 contains a disulfide pattern Cys1-Cys4/Cys2-Cys3, a secondary structure defined by a β-hairpin, and a N-terminal α-helix, which are characteristic motifs of Kunitz-type structures. The peptide Tt7 was both chemically and biologically synthesized. The recombinant peptides (rTt7 and HisrTt7) showed analgesic effects. Electrophysiological analyses of Tt7 on the voltage-gated sodium channel (Na v ) subtype 1.7 reduced the Na + current by ca 10%. Further studies showed that Tt7 inhibits the pH gated Ca-fluorescence increase in dorsal root ganglion neurons of the rat, indicating an inhibitory action of Tt7 in the acid gated currents which may account for the observed analgesic action of Tt7, suggesting that this peptide might affect various pain-related receptors. [ABSTRACT FROM AUTHOR]

Key points The release probability of the odorant receptor neuron (ORN) is reportedly one of the highest in the brain and is predicted to impose a transient temporal filter on postsynaptic cells., Mitral cells responded to high frequency ORN stimulation with sustained transmission, whereas external tufted cells responded transiently., The release probability of ORNs (0.7) was equivalent across mitral and external tufted cells and could be explained by a single pool of slowly recycling vesicles., The sustained response in mitral cells resulted from dendrodendritic amplification in mitral cells, which was blocked by NMDA and mGluR1 receptor antagonists, converting mitral cell responses to transient response profiles., Our results suggest that although the afferent ORN synapse shows strong synaptic depression, dendrodendritic circuitry in mitral cells produces robust amplification of brief afferent input, and thus the relative strength of axodendritic and dendrodendritic input determines the postsynaptic response profile., Abstract Short-term synaptic plasticity is a critical regulator of neural circuits, and largely determines how information is temporally processed. In the olfactory bulb, afferent olfactory receptor neurons respond to increasing concentrations of odorants with barrages of action potentials, and their terminals have an extraordinarily high release probability. These features suggest that during naturalistic stimuli, afferent input to the olfactory bulb is subject to strong synaptic depression, presumably truncating the postsynaptic response to afferent stimuli. To examine this issue, we used single glomerular stimulation in mouse olfactory bulb slices to measure the synaptic dynamics of afferent-evoked input at physiological stimulus frequencies. In cell-attached recordings, mitral cells responded to high frequency stimulation with sustained responses, whereas external tufted cells responded transiently. Consistent with previous reports, olfactory nerve terminals onto both cell types had a high release probability (0.7), from a single pool of slowly recycling vesicles, indicating that the distinct responses of mitral and external tufted cells to high frequency stimulation did not originate presyaptically. Rather, distinct temporal response profiles in mitral cells and external tufted cells could be attributed to slow dendrodendritic responses in mitral cells, as blocking this slow current in mitral cells converted mitral cell responses to a transient response profile, typical of external tufted cells. Our results suggest that despite strong axodendritic synaptic depression, the balance of axodendritic and dendrodendritic circuitry in external tufted cells and mitral cells, respectively, tunes the postsynaptic responses to high frequency, naturalistic stimulation. [ABSTRACT FROM AUTHOR]

Key points Pharmacological, molecular and genetic data indicate a prominent role of low-voltage-activated T-type calcium channels (T-channels) in the firing activity of both pyramidal and inhibitory interneurons in the subiculum., Pharmacological inhibition of T-channels switched burst firing with lower depolarizing stimuli to regular spiking, and fully abolished hyperpolarization-induced burst firing., Our molecular studies showed that CaV3.1 is the most abundantly expressed isoform of T-channels in the rat subiculum., Consistent with this finding, both regular-spiking and burst firing patterns were profoundly depressed in the mouse with global deletion of CaV3.1 isoform of T-channels., Selective inhibition of T-channels and global deletion of CaV3.1 channels completely suppressed development of long-term potentiation (LTP) in the CA1-subiculum, but not in the CA3-CA1 pathway., Abstract Several studies suggest that voltage-gated calcium currents are involved in generating high frequency burst firing in the subiculum, but the exact nature of these currents remains unknown. Here, we used selective pharmacology, molecular and genetic approaches to implicate Cav3.1-containing T-channels in subicular burst firing, in contrast to several previous reports discounting T-channels as major contributors to subicular neuron physiology. Furthermore, pharmacological antagonism of T-channels, as well as global deletion of CaV3.1 isoform, completely suppressed development of long-term potentiation (LTP) in the CA1-subiculum, but not in the CA3-CA1 pathway. Our results indicate that excitability and synaptic plasticity of subicular neurons relies heavily on T-channels. Hence, T-channels may be a promising new drug target for different cognitive deficits. [ABSTRACT FROM AUTHOR]