Effect of Synthesis Factors on Microstructure and Thermoelectric Properties of FeTe2 Prepared by Solid-State Reaction.

The alloying compound FeTe2 is a semi-metallic material with low thermal conductivity and has the potential to become a thermoelectric material. Single-phase FeTe2 compounds are synthesized using a two-step sintering method, and the effects of the optimal sintering temperature, holding temperature, and holding time on the thermoelectric properties of the alloy compound FeTe2 are investigated. The phase composition, microstructure, and electrical transport properties of the FeTe2 compound are systematically analyzed. The results show that single-phase FeTe2 compounds can be synthesized within the range of a sintering temperature of 823 K and holding time of 10~60 min, and the thermoelectric properties gradually deteriorate with the prolongation of the holding time. Microstructural analysis reveals that the sample of the alloy compound FeTe2 exhibits a three-dimensional network structure with numerous fine pores, which can impede thermal conduction and thus reduce the overall thermal conductivity of the material. When the sintering temperature is 823 K and the holding time is 30 min, the sample achieves the minimum electrical resistivity of 6.9 mΩ·cm. The maximum Seebeck coefficient of 65.48 µV/K is obtained when the sample is held at 823 K for 10 min; and under this condition, the maximum power factor of 59.54 µW/(m·K2) is achieved. In the whole test temperature range of 323~573 K, when the test temperature of the sample is 375 K, the minimum thermal conductivity is 1.46 W/(m·K), and the maximum ZT is 1.57 × 10-2.

Differential expression of slow and fast-repriming tetrodotoxin-sensitive sodium currents in dorsal root ganglion neurons.

Sodium channel Nav1.7 triggers the generation of nociceptive action potentials and is important in sending pain signals under physiological and pathological conditions. However, studying endogenous Nav1.7 currents has been confounded by co-expression of multiple sodium channel isoforms in dorsal root ganglion (DRG) neurons. In the current study, slow-repriming (SR) and fast-repriming (FR) tetrodotoxin-sensitive (TTX-S) currents were dissected electrophysiologically in small DRG neurons of both rats and mice. Three subgroups of small DRG neurons were identified based on the expression pattern of SR and FR TTX-S currents. A majority of rat neurons only expressed SR TTX-S currents, while a majority of mouse neurons expressed additional FR TTX-S currents. ProTx-II inhibited SR TTX-S currents with variable efficacy among DRG neurons. The expression of both types of TTX-S currents was higher in Isolectin B4-negative (IB4-) compared to Isolectin B4-positive (IB4+) neurons. Paclitaxel selectively increased SR TTX-S currents in IB4- neurons. In simulation experiments, the Nav1.7-expressing small DRG neuron displayed lower rheobase and higher frequency of action potentials upon threshold current injections compared to Nav1.6. The results suggested a successful dissection of endogenous Nav1.7 currents through electrophysiological manipulation that may provide a useful way to study the functional expression and pharmacology of endogenous Nav1.7 channels in DRG neurons.

Development of charybdotoxin Q18F variant as a selective peptide blocker of neuronal BK(α + ß4) channel for the treatment of epileptic seizures.

Epilepsy is the results from the imbalance between inhibition and excitation in neural circuits, which is mainly treated by some chemical drugs with side effects. Gain-of-function of BK channels or knockout of its ß4 subunit associates with spontaneous epilepsy. Currently, few reports were published about the efficacy of BK(α + ß4) channel modulators in epilepsy prevention. Charybdotoxin is a non-specific inhibitor of BK and other K+ channels. Here, by nuclear magnetic resonance (NMR) and other biochemical techniques, we found that charybdotoxin might interact with the extracellular loop of human ß4 subunit (i.e., hß4-loop) of BK(α + ß4) channel at a molar ratio 4:1 (hß4-loop vs. charybdotoxin). Charybdotoxin enhanced its ability to prevent K+ current of BK(α + ß4 H101Y) channel. The charybdotoxin Q18F variant selectively reduced the neuronal spiking frequency and increased interspike intervals of BK(α + ß4) channel by π-π stacking interactions between its residue Phe18 and residue His101 of hß4-loop. Moreover, intrahippocampal infusion of charybdotoxin Q18F variant significantly increased latency time of seizure, reduced seizure duration and seizure numbers on pentylenetetrazole-induced pre-sensitized rats, inhibited hippocampal hyperexcitability and c-Fos expression, and displayed neuroprotective effects on hippocampal neurons. These results implied that charybdotoxin Q18F variant could be potentially used for intractable epilepsy treatment by therapeutically targeting BK(α + ß4) channel.

Low-intensity exercise combined with sodium valproate attenuates kainic acid-induced seizures and associated co-morbidities by inhibiting NF-κB signaling in mice.

Sodium valproate (VPA) is a broad-spectrum anticonvulsant that is effective both in adults and children suffering from epilepsy, but it causes psychiatric and behavioral side effects in patients with epilepsy. In addition, 30% of patients with epilepsy develop resistance to VPA. At present, regular physical exercise has shown many benefits and has become an effective complementary therapy for various brain diseases, including epilepsy. Therefore, we wondered whether VPA combined with exercise would be more effective in the treatment of seizures and associated co-morbidities. Here, we used a mouse model with kainic acid (KA)-induced epilepsy to compare the seizure status and the levels of related co-morbidities, such as cognition, depression, anxiety, and movement disorders, in each group using animal behavioral experiment and local field potential recordings. Subsequently, we investigated the mechanism behind this phenomenon by immunological means. Our results showed that low-intensity exercise combined with VPA reduced seizures and associated co-morbidities. This phenomenon seems to be related to the Toll-like receptor 4, activation of the nuclear factor kappa B (NF-κB), and release of interleukin 1ß (IL-1ß), tumor necrosis factor α (TNF-α), and IL-6. In brief, low-intensity exercise combined with VPA enhanced the downregulation of NF-κB-related inflammatory response, thereby alleviating the seizures, and associated co-morbidities.

Anti-epileptic/pro-epileptic effects of sodium channel modulators from Buthus martensii Karsch.

The East Asian scorpion Buthus martensii Karsch (BmK) is one of the classical traditional Chinese medicines for treating epilepsy for over a thousand years. Neurotoxins purified from BmK venom are considered as the main active ingredients, acting on membrane ion channels. Voltage-gated sodium channels (VGSCs) play a crucial role in the occurrence of epilepsy, which make them become important drug targets for epilepsy. Long chain toxins of BmK, composed of 60-70 amino acid residues, could specifically recognize VGSCs. Among them, α-like neurotoxins, binding to the receptor site-3 of VGSC, induce epilepsy in rodents and can be used to establish seizure models. The ß or ß-like neurotoxins, binding to the receptor site-4 of VGSC, have significant anticonvulsant effects in epileptic models. This review aims to illuminate the anticonvulsant/convulsant effects of BmK polypeptides by acting on VGSCs, and provide potential frameworks for the anti-epileptic drug-design.

Aerobic Physical Exercise as a Non-medical Intervention for Brain Dysfunction: State of the Art and Beyond.

Brain disorders, including stroke, Alzheimer's disease, depression, and chronic pain, are difficult to effectively treat. These major brain disorders have high incidence and mortality rates in the general population, and seriously affect not only the patient's quality of life, but also increases the burden of social medical care. Aerobic physical exercise is considered an effective adjuvant therapy for preventing and treating major brain disorders. Although the underlying regulatory mechanisms are still unknown, systemic processes may be involved. Here, this review aimed to reveal that aerobic physical exercise improved depression and several brain functions, including cognitive functions, and provided chronic pain relief. We concluded that aerobic physical exercise helps to maintain the regulatory mechanisms of brain homeostasis through anti-inflammatory mechanisms and enhanced synaptic plasticity and inhibition of hippocampal atrophy and neuronal apoptosis. In addition, we also discussed the cross-system mechanisms of aerobic exercise in regulating imbalances in brain function, such as the "bone-brain axis." Furthermore, our findings provide a scientific basis for the clinical application of aerobic physical exercise in the fight against brain disorders.

Homology modeling and molecular docking simulation of martentoxin as a specific inhibitor of the BK channel.

Background: Large conductance calcium-activated potassium channel (BK channel) is gated by both voltage and calcium ions and is widely distributed in excitable and nonexcitable cells. BK channel plays an important role in epilepsy and other diseases, but BK channel subtype-specific drugs are still extremely rare. Martentoxin was previously isolated from the venom of members of Scorpionidae and shown to be composed of 37 amino acids. Research has shown that the pharmacological selectivity of martentoxin to the BK channel is higher than that to other potassium channels. Therefore, it is of great significance to study the mechanism of interaction between martentoxin and BK channels. Methods: The three-dimensional structure of BK channel pore region was constructed by homologous modeling method, and the key amino acid sites of BK channel interaction with martentoxin were analyzed by protein-protein docking, molecular dynamic simulation and virtual alanine mutation. Results: Based on homologous modeling of BK channel pore structure and protein-protein docking analysis, Phe1, Lys28 and Arg35 of martentoxin were found to be key amino acids in toxin BK channel interaction. Conclusions: This study reveals the structural basis of martentoxin interaction with BK channel. These results will contribute to the design of BK channel specific blockers based on the structure of martentoxin.

Oxaliplatin Depolarizes the IB4- Dorsal Root Ganglion Neurons to Drive the Development of Neuropathic Pain Through TRPM8 in Mice.

Use of chemotherapy drug oxaliplatin is associated with painful peripheral neuropathy that is exacerbated by cold. Remodeling of ion channels including TRP channels in dorsal root ganglion (DRG) neurons contribute to the sensory hypersensitivity following oxaliplatin treatment in animal models. However, it has not been studied if TRP channels and membrane depolarization of DRG neurons serve as the initial ionic/membrane drives (such as within an hour) that contribute to the development of oxaliplatin-induced neuropathic pain. In the current study, we studied in mice (1) in vitro acute effects of oxaliplatin on the membrane excitability of IB4+ and IB4- subpopulations of DRG neurons using a perforated patch clamping, (2) the preventative effects of a membrane-hyperpolarizing drug retigabine on oxaliplatin-induced sensory hypersensitivity, and (3) the preventative effects of TRP channel antagonists on the oxaliplatin-induced membrane hyperexcitability and sensory hypersensitivity. We found (1) IB4+ and IB4- subpopulations of small DRG neurons displayed previously undiscovered, substantially different membrane excitability, (2) oxaliplatin selectively depolarized IB4- DRG neurons, (3) pretreatment of retigabine largely prevented oxaliplatin-induced sensory hypersensitivity, (4) antagonists of TRPA1 and TRPM8 channels prevented oxaliplatin-induced membrane depolarization, and (5) the antagonist of TRPM8 largely prevented oxaliplatin-induced sensory hypersensitivity. These results suggest that oxaliplatin depolarizes IB4- neurons through TRPM8 channels to drive the development of neuropathic pain and targeting the initial drives of TRPM8 and/or membrane depolarization may prevent oxaliplatin-induce neuropathic pain.

Glycosylation of ß1 subunit plays a pivotal role in the toxin sensitivity and activation of BK channels.

BACKGROUND: The accessory ß1 subunits, regulating the pharmacological and biophysical properties of BK channels, always undergo post-translational modifications, especially glycosylation. To date, it remains elusive whether the glycosylation contributes to the regulation of BK channels by ß1 subunits. METHODS: Herein, we combined the electrophysiological approach with molecular mutations and biochemical manipulation to investigate the function roles of N-glycosylation in ß1 subunits. RESULTS: The results show that deglycosylation of ß1 subunits through double-site mutations (ß1 N80A/N142A or ß1 N80Q/N142Q) could significantly increase the inhibitory potency of iberiotoxin, a specific BK channel blocker. The deglycosylated channels also have a different sensitivity to martentoxin, another BK channel modulator with some remarkable effects as reported before. On the contrary to enhancing effects of martentoxin on glycosylated BK channels under the presence of cytoplasmic Ca2+, deglycosylated channels were not affected by the toxin. However, the deglycosylated channels were surprisingly inhibited by martentoxin under the absence of cytoplasmic Ca2+, while the glycosylated channels were not inhibited under this same condition. In addition, wild type BK (α+ß1) channels treated with PNGase F also showed the same trend of pharmacological results to the mutants. Similar to this modulation of glycosylation on BK channel pharmacology, the deglycosylated forms of the channels were activated at a faster speed than the glycosylated ones. However, the V1/2 and slope were not changed by the glycosylation. CONCLUSION: The present study reveals that glycosylation is an indispensable determinant of the modulation of ß1-subunit on BK channel pharmacology and its activation. The loss of glycosylation of ß1 subunits could lead to the dysfunction of BK channel, resulting in a pathological state.

CCT128930 is a novel and potent antagonist of TRPM7 channel.

Transient receptor potential melastatin 7 (TRPM7) channels represent a major magnesium (Mg2+)-uptake component in mammalian cells and are negatively modulated by internal Mg2+. However, few TRPM7 modulators were identified so far, which hindered the understanding of the TRPM7 channel functions. In this study, we identified that CCT128930, an ATP-competitive protein kinase B inhibitor reported previously, was a potent TRPM7 channel antagonist. The inhibition of CCT128930 on TRPM7 was independent of intracellular Mg2+. In the absence and presence of 300 µM Mg2+ in pipette solution, the IC50 values were 0.86 ± 0.11 µM and 0.63 ± 0.09 µM, respectively. Subtype selectivity data showed that CCT128930 preferentially inhibited TRPM7 channels compared to TRPM6 and TRPM8 isoforms. In addition, CCT128930 was found to be able to reduce the endogenous TRPM7-like currents in SH-SY5Y neuroblastoma cells. At last, multiple residues in the superficial part of the TRPM7 selectivity filter were identified to be critical for the inhibitory activity of CCT128930 which are different from the determinants of Mg2+ and reported TRPM7 antagonists. Our results indicated that CCT128930 is a novel and potent TRPM7 channel antagonist.

[The new target of Rapamycin: lysosomal calcium channel TRPML1].

Rapamycin (Rap) is an immunosuppressant, which is mainly used in the anti-rejection of organ transplantation. Meanwhile, it also shows great potential in the fields of anticancer, neuroprotection and anti-aging. Rap can inhibit the activity of mammalian target of Rap (mTOR). It activates the transcription factor EB (TFEB) to up-regulate lysosomal function and eliminates the inhibitory effect of mTOR on ULK1 (unc-51 like autophagy activating kinase 1) to promote autophagy. Recent research showed that Rap can directly activate the lysosomal cation channel TRPML1 in an mTOR-independent manner. TRPML1 activation releases lysosomal calcium. Calcineurin functions as the sensor of the lysosomal calcium signal and activates TFEB, thus promoting lysosome function and autophagy. This finding has greatly broadened and deepened our understanding of the pharmacological roles of Rap. In this review, we briefly introduce the canonical Rap-mTOR-ULK1/TFEB signaling pathway, and then discuss the discovery of TRPML1 as a new target of Rap and the pharmacological potential of this novel Rap-TRPML1-Calcineurin-TFEB pathway.

Stress-related hormone reduces autophagy through the regulation of phosphatidylethanolamine in breast cancer cells.

BACKGROUND: An increasing number of studies indicate that adrenergic signaling plays a fundamental role in tumor progression and metastasis induced by chronic stress. However, despite the growing attention, an understanding of the mechanisms linking chronic stress and cancer is still insufficient. METHODS: Western blot analysis and transmission electron microscopy (TEM) were used to observe the changes in autophagy level in a breast cancer cell line (MCF-7) after epinephrine treatment. Non-targeted metabolomics was also used to detect MCF-7 metabolites after epinephrine treatment. The xenograft model was used to detect the level of autophagy after epinephrine intervention. RESULTS: The results showed that epinephrine treatment reduced the autophagy level of breast cancer cells. Epinephrine changed the level of phosphatidylethanolamine (PE) in breast cancer cells as detected by non-targeted metabolomics. Epinephrine also changed autophagy in breast cancer cells by decreasing the level of PE in cells. When autophagy decreased, the invasion and migration of breast cancer cells increased in vitro, and the progression of breast cancer accelerated in vivo. CONCLUSIONS: These findings suggest that stress-related hormones affect the tumor progression of breast cancer. Therefore, strengthening the emotional management strategies of patients during the process of antitumor treatment as a supplement to the existing treatments may be beneficial.

Molecular Mechanisms of Epileptic Encephalopathy Caused by KCNMA1 Loss-of-Function Mutations.

The gene kcnma1 encodes the α-subunit of high-conductance calcium- and voltage-dependent K+ (BK) potassium channel. With the development of generation gene sequencing technology, many KCNMA1 mutants have been identified and are more closely related to generalized epilepsy and paroxysmal dyskinesia. Here, we performed a genetic screen of 26 patients with febrile seizures and identified a novel mutation of KCNMA1 (E155Q). Electrophysiological characterization of different KCNMA1 mutants in HEK 293T cells, the previously-reported R458T and E884K variants (not yet determined), as well as the newly-found E155Q variant, revealed that the current density amplitude of all the above variants was significantly smaller than that of the wild-type (WT) channel. All the above variants caused a positive shift of the I-V curve and played a role through the loss-of-function (LOF) mechanism. Moreover, the ß4 subunit slowed down the activation of the E155Q mutant. Then, we used kcnma1 knockout (BK KO) mice as the overall animal model of LOF mutants. It was found that BK KO mice had spontaneous epilepsy, motor impairment, autophagic dysfunction, abnormal electroencephalogram (EEG) signals, as well as possible anxiety and cognitive impairment. In addition, we performed transcriptomic analysis on the hippocampus and cortex of BK KO and WT mice. We identified many differentially expressed genes (DEGs). Eight dysregulated genes [i.e., (Gfap and Grm3 associated with astrocyte activation) (Alpl and Nlrp10 associated with neuroinflammation) (Efna5 and Reln associated with epilepsy) (Cdkn1a and Nr4a1 associated with autophagy)] were validated by RT-PCR, which showed a high concordance with transcriptomic analysis. Calcium imaging results suggested that BK might regulate the autophagy pathway from TRPML1. In conclusion, our study indicated that newly-found point E155Q resulted in a novel loss-of-function variant and the dysregulation of gene expression, especially astrocyte activation, neuroinflammation and autophagy, might be the molecular mechanism of BK-LOF meditated epilepsy.

Glycosylation of ß1 subunit plays a pivotal role in the toxin sensitivity and activation of BK channels

The accessory ß1 subunits, regulating the pharmacological and biophysical properties of BK channels, always undergo post-translational modifications, especially glycosylation. To date, it remains elusive whether the glycosylation contributes to the regulation of BK channels by ß1 subunits. Methods: Herein, we combined the electrophysiological approach with molecular mutations and biochemical manipulation to investigate the function roles of N-glycosylation in ß1 subunits. Results: The results show that deglycosylation of ß1 subunits through double-site mutations (ß1 N80A/N142A or ß1 N80Q/N142Q) could significantly increase the inhibitory potency of iberiotoxin, a specific BK channel blocker. The deglycosylated channels also have a different sensitivity to martentoxin, another BK channel modulator with some remarkable effects as reported before. On the contrary to enhancing effects of martentoxin on glycosylated BK channels under the presence of cytoplasmic Ca2+, deglycosylated channels were not affected by the toxin. However, the deglycosylated channels were surprisingly inhibited by martentoxin under the absence of cytoplasmic Ca2+, while the glycosylated channels were not inhibited under this same condition. In addition, wild type BK (α+ß1) channels treated with PNGase F also showed the same trend of pharmacological results to the mutants. Similar to this modulation of glycosylation on BK channel pharmacology, the deglycosylated forms of the channels were activated at a faster speed than the glycosylated ones. However, the V1/2 and slope were not changed by the glycosylation. Conclusion: The present study reveals that glycosylation is an indispensable determinant of the modulation of ß1-subunit on BK channel pharmacology and its activation. The loss of glycosylation of ß1 subunits could lead to the dysfunction of BK channel, resulting in a pathological state.(AU)

Neuroglial activation in the auditory cortex and medial geniculate body of salicylate-induced tinnitus rats.

Neuroglial activation has been recognized as a pathological hallmark of a variety of neurological diseases, yet the role of neuroglia in tinnitus hasn't been well established so far. To explore the potential roles of two types of glia cells (astrocyte and microglia) in the development of tinnitus, we examined markers associated with them in the primary auditory (A1) cortex and medial geniculate body (MGB) of rats with salicylate-induced tinnitus. The results demonstrated that acute and chronic administrations of salicylate could cause reversible tinnitus-like behavior in rats. The expression level of GFAP markedly increased in the A1 cortex of rats following acute and chronic treatments of salicylate, accompanied by increased endpoint and process length of astrocyte. The expression level of GFAP and the morphology of astrocyte in the rat MGB remained almost constant following salicylate treatment. On the other hand, the expression level of Iba1 markedly increased in the rat A1 cortex and MGB following acute and chronic treatments of salicylate, together with increased endpoint and process length of microglia in the MGB. Additionally, interleukin 1ß (IL-1ß), a pro-inflammatory cytokine released by activated glia was significantly up-regulated in the A1 cortex and MGB of rats after salicylate treatments. These findings highlight astrocyte activation and microglia proliferation in the central auditory system of rats experiencing tinnitus, which potently implicate an indispensable glial regulation in tinnitus development.

GPR68 Is a Neuroprotective Proton Receptor in Brain Ischemia.

BACKGROUND AND PURPOSE: Brain acidosis is prevalent in stroke and other neurological diseases. Acidosis can have paradoxical injurious and protective effects. The purpose of this study is to determine whether a proton receptor exists in neurons to counteract acidosis-induced injury. METHODS: We analyzed the expression of proton-sensitive GPCRs (G protein-coupled receptors) in the brain, examined acidosis-induced signaling in vitro, and studied neuronal injury using in vitro and in vivo mouse models. RESULTS: GPR68, a proton-sensitive GPCR, was present in both mouse and human brain, and elicited neuroprotection in acidotic and ischemic conditions. GPR68 exhibited wide expression in brain neurons and mediated acidosis-induced PKC (protein kinase C) activation. PKC inhibition exacerbated pH 6-induced neuronal injury in a GPR68-dependent manner. Consistent with its neuroprotective function, GPR68 overexpression alleviated middle cerebral artery occlusion-induced brain injury. CONCLUSIONS: These data expand our knowledge on neuronal acid signaling to include a neuroprotective metabotropic dimension and offer GPR68 as a novel therapeutic target to alleviate neuronal injuries in ischemia and multiple other neurological diseases.

Downregulation of MicroRNA-34c-5p facilitated neuroinflammation in drug-resistant epilepsy.

Drug-resistant epilepsy patients has aberrant inflammatory mediator levels. However, the mechanism of which is remains unillustrated. Here the molecular mechanism underlying the neuroinflammatory process in patients with drug-resistant epilepsy were investigated. Bioinformatics analysis revealed that miR-34c-5p was significantly downregulated in patients with drug-resistant epilepsy, compared to control population. Then, luciferase reporter assays indicated that HMGB1, inflammation-related mediators, was the target gene of miR-34c-5p. The kainic acid-induced epileptic rats were established and divided into drug-sensitive epilepsy and drug-resistant epilepsy according to their seizure behavior and EEG after antiepileptic drug administration. Downregulation of miR-34c-5p, elevated expression of HMGB1 and IL-1ß had been found in rats with drug-resistant epilepsy, compared to drug-sensitive epilepsy rats. Aggravated hippocampal neuron loss was demonstrated in rats with drug-resistant epilepsy. The results from epileptic rats were subsequently validated from children with drug-resistant epilepsy. Analysis manifested that miR-34c-5p was obviously decreased, while HMGB1 was increased on serum of children with drug-resistant epilepsy. Our study highlights that decreased miR-34c-5p in drug-resistant epilepsy exacerbates neuroinflammation, which aggravates hippocampal neuron loss in epileptogenesis. Thus, miR-34c-5p could be considered as a potential noninvasive biomarker and shed novel light on the development of an effective therapeutic strategy for children with drug-resistant epilepsy in the future.

Aberrant expression of Nav1.6 in the cochlear nucleus correlates with salicylate-induced tinnitus in rats.

Hyperactivity in cochlear nucleus (CN) is one of the major neural correlates for tinnitus induction, yet the molecular factors that participate in the neuronal hyperexcitability remain unclear. The present study showed that acute and chronic administrations of salicylate were both capable of inducing reversible tinnitus in rats. The number of GAD 65/67-immunoreactive neurons in the AVCN and DCN was decreased, while the number of VGLUT 1/2-immunoreactive neurons in the AVCN and DCN was increased when rats were experiencing tinnitus, providing evidence for excitatory-inhibitory imbalance in CN is correlated with tinnitus. Interestingly, the expression level of Nav1.6, an important subtype of voltage-gated sodium channels was significantly increased in the DCN and AVCN of rats experiencing tinnitus, the up-regulation of Nav1.6 was returned to normal level following the disappearance of tinnitus. Double-labeling experiments revealed that Nav1.6 expression was down-regulated in the GAD 65/67-positive neurons in the DCN and AVCN of rats experiencing tinnitus. Notably, the percentage of co-localization of Nav1.6 and NeuN-labeling fusiform neurons was markedly increased in the DCN during tinnitus. These findings uncover the tinnitus-associated alteration in Nav1.6, a potential key contributor that can lead to hyperexcitability in CN and contribute to salicylate-induced tinnitus.

Identifying the toxins in hornet (Vespa basalis) venom that induce rat pain responses.

The black-bellied hornet Vespa basalis is responsible for the large quantity of accidents and severe wasp envenomation in China. This study aims to identify the rat pain responses induced by experimental V. basalis sting and related-components in the venom. It was observed that unilateral intraplantar injection of crude V. basalis venom could induce several kinds of pain related behaviors in a dose-dependent manner including spontaneous pain, unilateral thermal and unilateral mechanical hypersensitivity at different time courses. Fourteen main fractions were separated from the crude venom of V. basalis using high performance liquid chromatography, among them, five components (1, 3, 4, 9 and 12) could absolutely mimic the crude venom-induced pain behaviors. According to the molecular mass and N-terminal sequence, the component 3 and 4 were identified as Mastoparan B and HP-1 respectively, the component 9 was speculated as a novel variant of HP-1/2. In addition, the other two sub-components (1-1 and 1-2) purified from component 1 cannot be determined. The results offered the key information about six active polypeptides from V. basalis contributing to pain responses, which might provide a basis for exploring mechanisms of wasp sting injury.