Association analysis of single nucleotide polymorphisms in the promoter region of GAD1 and GABRB3 with schizophrenia in Chinese Han population / 上海交通大学学报（医学版）

Objective: To investigate the correlation between the polymorphisms of locus in the promoter region of glutamate decarboxylase 1 (GAD1) gene and γ-aminobutyric acid (GABA)A receptor β-3 gene (GABRB3) and schizophrenia (SZ) in Chinese Han population. Methods: SNaPshot genotyping technique was used to detect the polymorphisms of rs3791878 and rs3749034 in the promoter region of GAD1 and rs4906902 in the promoter region of GABRB3 in 545 SZ patients (case group) and 624 healthy controls (control group). The distribution of alleles and genotypes under different genetic models between the case group and the control group in all samples were compared by SNPstats online software. The above analysis was also performed after the subjects were stratified according to gender. The correlation of G/T risk genotype of rs3791878 with the age of the first onset of male SZ was investigated by survival analysis. Results: Under over-dominant genetic model, the distribution of G/T risk genotype of rs3791878 showed statistically difference between the male SZ cases and male controls (P=0.000), and the difference was still statistically significant after Bonferroni correction (P=0.000). However, there was no significant difference in the distribution of alleles and genotypes under different genetic models of rs3749034 and rs4906902 between the case group and the control group in all samples (P>0.05), and there was also no significant difference in the distribution of alleles between the case group and the control group after them being stratified according to gender (P>0.05). Kaplan-Meier analysis showed that there was no significant difference between the age of onset of male SZ who carried G/T genotype in rs3791878 locus and that of male SZ who did not carry it (P=0.603). Conclusion: The polymorphism of rs3791878 in the promoter region of GAD1 is significantly associated with the incidence of male SZ in Chinese Han population.

Neurosteroids: current perspective in therapy of neuropsychiatric disorders

Neurosteroids are natural or synthetic steroid derivatives which act locally in brain by modulating neuronal excitability. The objective of this study is to analyze available literature on classification, biosynthesis and mechanism of action, and therapeutic potential of neurosteroids. A review of literature pertaining to neurosteroids published from inception to 2018 was carried on data bases like PUBMED, Google Scholar and Science Direct. The search terms used were neurosteroids, neuro-active steroids, ganaxolone and GABA-A receptor modulators. Review of literature suggests neurosteroids are powerful neuro-modulators, involving rapid non-genomic and non-hormone receptor mechanisms. They are classified based on structure as pregnane, androstane and sulphated neurosteroids, and based on function as excitatory or inhibitory neurosteroids. They act via GABAA receptor (primarily), rho- GABA (?GABA), NMDA-glutamate and sigma receptor modulation. The inhibitory neurosteroids demonstrate sedative, anxiolytic and anticonvulsant actions, whereas the excitatory agents produce memory enhancing and anxiogenic effects. They show efficacy in various CNS and psychiatric conditions like epilepsy, anxiety, depression, learning and memory disorders and substance abuse. Endogenous neurosteroids have limited clinical use due to low bioavailability, lack of specificity and unwanted effects. Hence, synthetic agents like alphaxalone, ganaxolone, sepranolone and brexanolone which have better bioavailability and specificity, are being investigated in various phases of clinical trials. Neurosteroids are novel endogenous compounds with neuro-modulatory function and show promising effects in therapy of various neurological and psychiatric conditions. Further studies that prove their long term efficacy and safety may revolutionize the clinical approach to therapy of these conditions.

Acetylcholinesterase inhibitory activity of a neurosteroidal alkaloid from the upside-down jellyfish Cassiopea andromeda venom

Abstract Natural compounds from marine organisms have been rarely studied for their acetylcholinesterase inhibitory activities. The aim of this study was to isolate novel compounds with antiAChE activity from the venom of upside-down jellyfish Cassiopea andromeda Forskål, 1775. The compounds of the fractionated venom on gel filtration chromatography were identified by analyzing gas chromatography-mass spectroscopy data. The structure of the isolated compound that showed the most potent antiAChE activity in a docking study was elucidated by different spectral data, including 1H NMR and 13C NMR. Three compounds, including a neurosteroidal alkaloid androtoxin B, were identified from two venom fractions. This neurosteroidal alkaloid showed strong acetylcholinesterase inhibitory activity (IC50 2.24 ± 0.1 µM) compared with the reference standard, galantamine. The results obtained by a docking study demonstrated that Androtoxin B had close contact with two of the three amino acid residues of the catalytic triad of acetylcholinesterase gorge and was accommodated within a peripheral hydrophobic pocket composed of numerous aromatic site chains. In conclusion, the isolated neurosteroidal alkaloid from Cassiopea andromeda was a potent antiAChE agent with strong binding to both the catalytic and peripheral sites of acetylcholinesterase that correlated well with the experimental data. Further studies are required to determine whether androtoxin B could be a potential treatment for Alzheimer's disease.

Administration of Alpha(s1)-Casein Hydrolysate Increases Sleep and Modulates GABA(A) Receptor Subunit Expression

Sleep is the most basic and essential physiological requirement for mental health, and sleep disorders pose potential risks of metabolic and neurodegenerative diseases. Tryptic hydrolysate of α(S1)-casein (α(S1)-CH) has been shown to possess stress relieving and sleep promoting effects. However, the differential effects of α(S1)-CH on electroencephalographic wave patterns and its effects on the protein levels of γ-aminobutyric acid A (GABA(A)) receptor subtypes in hypothalamic neurons are not well understood. We found α(S1)-CH (120, 240 mg/kg) increased sleep duration in mice and reduced sleep-wake cycle numbers in rats. While α(S1)-CH (300 mg/kg) increased total sleeping time in rats, it significantly decreased wakefulness. In addition, electroencephalographic theta (θ) power densities were increased whereas alpha (α) power densities were decreased by α(S1)-CH (300 mg/kg) during sleep-wake cycles. Furthermore, protein expressions of GABA(A) receptor β1 subtypes were elevated in rat hypothalamus by α(S1)-CH. These results suggest α(S1)-CH, through GABA(A) receptor modulation, might be useful for treating sleep disorders.

Activation of CD8+T cells regulated by γ-aminobutyric acid and its receptors / 器官移植

Objective To evaluate the effect of γ-aminobutyric acid (GABA) and its receptors upon the proliferation of CD8+T cells.Methods The splenic CD8+T cells of Balb/c mice were obtained by CD8+f cell magnetic bead sorting kit.Under the effect of CD3/CD28-activated magnetic bead,CD8+T cells were stimulated by different concentrations of GABA.5-bromo-2-deoxyuridine (BrdU) labeling and flow cytometry were performed to detect the proliferation of CD8+T cells.The expression levels of GABA-A and GABA-B receptor before and after CD8+T cell activation were compared by fluorescent quantitative real-time polymerase chain reaction (PCR).Result Flow cytometry result revealed that GABA could inhibit the proliferation of activated CD8+T cells,manifested as significant decrease in the quantity of CD152+CD8+T cells.Fluorescent quantitative real-time PCR demonstrated that GABA-A receptor subtypes α2,α6 and GABA-B receptor subtype 1a were expressed only when the CD8+T cells were activated.After CD8+T cell activation,the quantity of GABA-A receptor subtypes α3,αs,β2,β3,γ1,γ2 and θ were significantly increased,whereas the quantity of GABA-B2R and GABA-B1b did not significantly differ before and after CD8+T cell activation.Conclusions GABA can suppress the proliferation of activated CD8+T cells.The activation of CD8+T cells is regulated by GABA receptors.However,the underlying mechanism remains to be elucidated.

Expression Levels of GABA-A Receptor Subunit Alpha 3, Gabra3 and Lipoprotein Lipase, Lpl Are Associated with the Susceptibility to Acetaminophen-Induced Hepatotoxicity

Drug-induced liver injury (DILI) is the serious and fatal drug-associated adverse effect, but its incidence is very low and individual variation in severity is substantial. Acetaminophen (APAP)-induced liver injury accounts for >50% of reported DILI cases but little is known for the cause of individual variations in the severity. Intrinsic genetic variation is considered a key element but the identity of the genes was not well-established. Here, pre-biopsy method and microarray technique was applied to uncover the key genes for APAP-induced liver injury in mice, and a cause and effect experiment employing quantitative real-time PCR was conducted to confirm the correlation between the uncovered genes and APAP-induced hepatotoxicity. We identified the innately and differentially expressed genes of mice susceptible to APAP-induced hepatotoxicity in the pre-biopsied liver tissue before APAP treatment through microarray analysis of the global gene expression profiles (Affymetrix GeneChip® Mouse Gene 1.0 ST for 28,853 genes). Expression of 16 genes including Gdap10, Lpl, Gabra3 and Ccrn4l were significantly different (t-test: FDR <10%) more than 1.5 fold in the susceptible animals than resistant. To confirm the association with the susceptibility to APAP-induced hepatotoxicity, another set of animals were measured for the expression level of selected 4 genes (higher two and lower two genes) in the liver pre-biopsy and their sensitivity to APAP-induced hepatotoxicity was evaluated by post hoc. Notably, the expressions of Gabra3 and Lpl were significantly correlated with the severity of liver injury (p<0.05) demonstrating that these genes may be linked to the susceptibility to APAP-induced hepatotoxicity.

Participation of central GABAA receptors in the trigeminal processing of mechanical allodynia in rats

Here we investigated the central processing mechanisms of mechanical allodynia and found a direct excitatory link with low-threshold input to nociceptive neurons. Experiments were performed on male Sprague-Dawley rats weighing 230-280 g. Subcutaneous injection of interleukin 1 beta (IL-1β) (1 ng/10 µL) was used to produce mechanical allodynia and thermal hyperalgesia. Intracisternal administration of bicuculline, a gamma aminobutyric acid A (GABAA) receptor antagonist, produced mechanical allodynia in the orofacial area under normal conditions. However, intracisternal administration of bicuculline (50 ng) produced a paradoxical anti-allodynic effect under inflammatory pain conditions. Pretreatment with resiniferatoxin (RTX), which depletes capsaicin receptor protein in primary afferent fibers, did not alter the paradoxical anti-allodynic effects produced by the intracisternal injection of bicuculline. Intracisternal injection of bumetanide, an Na-K-Cl cotransporter (NKCC 1) inhibitor, reversed the IL-1β-induced mechanical allodynia. In the control group, application of GABA (100 µM) or muscimol (3 µM) led to membrane hyperpolarization in gramicidin perforated current clamp mode. However, in some neurons, application of GABA or muscimol led to membrane depolarization in the IL-1β-treated rats. These results suggest that some large myelinated Aβ fibers gain access to the nociceptive system and elicit pain sensation via GABA(A) receptors under inflammatory pain conditions.

Sedative-Hypnotic and Receptor Binding Studies of Fermented Marine Organisms

This study was performed to investigate the sedative-hypnotic activity of gamma-aminobutyric acid (GABA)-enriched fermented marine organisms (FMO), including sea tangle (FST) and oyster (FO) by Lactobacillus brevis BJ20 (L. brevis BJ20). FST and FO were tested for their binding activity of the GABA(A)-benzodiazepine and 5-HT(2C) receptors, which are well-known molecular targets for sleep aids. We also measured the sleep latency and sleep duration during pentobarbital-induced sleep in mice after oral administration of FST and FO. In GABA(A) and 5-HT(2C) receptor binding assays, FST displayed an effective concentration-dependent binding affinity to GABA(A) receptor, similar to the binding affinity to 5-HT(2C) receptor. FO exhibited higher affinity to 5-HT(2C) receptor, compared with the GABA(A) receptor. The oral administration of FST and FO produced a dose-dependent decrease in sleep latency and increase in sleep duration in pentobarbital-induced hypnosis. The data demonstrate that FST and FO possess sedative-hypnotic activity possibly by modulating GABA(A) and 5-HT(2C) receptors. We propose that FST and FO might be effective agents for treatment of insomnia.

Enhancement of GluN2B Subunit-Containing NMDA Receptor Underlies Serotonergic Regulation of Long-Term Potentiation after Critical Period in the Rat Visual Cortex

Serotonin [5-hydroxytryptamine (5-HT)] regulates synaptic plasticity in the visual cortex. Although the effects of 5-HT on plasticity showed huge diversity depending on the ages of animals and species, it has been unclear how 5-HT can show such diverse effects. In the rat visual cortex, 5-HT suppressed long-term potentiation (LTP) at 5 weeks but enhanced LTP at 8 weeks. We speculated that this difference may originate from differential regulation of neurotransmission by 5-HT between the age groups. Thus, we investigated the effects of 5-HT on apha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-, gamma-aminobutyric acid receptor type A (GABA(A)R)-, and N-methyl-D-aspartic acid receptor (NMDAR)-mediated neurotransmissions and their involvement in the differential regulation of plasticity between 5 and 8 weeks. AMPAR-mediated currents were not affected by 5-HT at both 5 and 8 weeks. GABA(A)R-mediated currents were enhanced by 5-HT at both age groups. However, 5-HT enhanced NMDAR-mediated currents only at 8 weeks. The enhancement of NMDAR-mediated currents appeared to be mediated by the enhanced function of GluN2B subunit-containing NMDAR. The enhanced GABA(A)R- and NMDAR-mediated neurotransmissions were responsible for the suppression of LTP at 5 weeks and the facilitation of LTP at 8 weeks, respectively. These results indicate that the effects of 5-HT on neurotransmission change with development, and the changes may underlie the differential regulation of synaptic plasticity between different age groups. Thus, the developmental changes in 5-HT function should be carefully considered while investigating the 5-HT-mediated metaplastic control of the cortical network.

Efecto de la alopregnanolona sobre la ansiedad en ratas con separación materna durante la lactancia / The effect of allopregnanolone on anxiety induced in rats separated from their young during breastfeeding

Antecedentes. La relación madre-hijo y el cuidado parental al recién nacido son fundamentales en el desarrollo fisiológico y emocional de los individuos. Evidencias asocian el estrés temprano con el desarrollo de enfermedades mentales. El modelo de separación materna durante la lactancia (SMDL) se ha utilizado para inducir estrés temprano en ratas y estudiar efectos a largo plazo. Diversos estudios han encontrado que, en ratas separadas de sus madres, disminuyen los niveles del receptor GABA-A y esos bajos niveles están asociados a comportamientos ansiosos. Objetivo. Evaluar el efecto de la alopregnanolona, un neuroesteroide agonista del receptor GABA-A, sobre la ansiedad inducida por SMDL. Materiales y métodos. Se utilizaron 30 ratas Wistar dividas en dos grupos, uno control y uno experimental (SMDL). La SMDL se realizó desde el día postnatal 1 hasta el día postnatal 21, durante 180 minutos en la mañana y 180 minutos en la tarde. Desde el día 22 los sujetos se alojaron en cajas por sexo y tratamiento y continuaron su desarrollo normal hasta el día 60, en el que se hizo la inyección con alopregnanolona y la prueba comportamental en el laberinto en cruz elevado. Resultados. El estrés crónico causado por la SMDL afecta el comportamiento de los individuos, perfil comportamental que varía dependiendo del sexo. Se encontró que los machos presentan comportamientos más ansiosos que las hembras, las cuales a su vez muestran más actividad locomotora y exploración Conclusiones. Al aplicar alopregnanolona el repertorio comportamental varía en los animales con SMDL; estos resultados sugieren que la alopregnanolona, a través de su unión al receptor GABA-A, puede llegar a revertir los efectos de la separación materna, sobre los comportamientos relacionados con ansiedad.

Background. The mother-child relationship and parental care for the newborn are fundamental in individuals' physiological and emotional development. Evidence-based research associates early stress with the development of mental illnesses. Maternal separation during lactation (MSDL) models have been used to induce early stress in rats and for studying the long-term effects of such intervention. Several studies have found decreased GABA-A receptor levels in separated rats from their mothers and such low levels have been associated with anxious behaviour. Objective. Assessing the effect of allopregnanolone (a GABA-A receptor neurosteroid agonist) on MSDL-induced anxiety. Materials and methods. Thirty Wistar rats were divided into two groups: control and experimental (MSDL). SMDL occurred for 180 minutes in the morning and 180 minutes in the afternoon. Subjects were housed in boxes by gender and treatment following day 22 and their normal development was allowed to continue until day 60 when they were injected with allopregnanolone and underwent a behavioural test in an elevated plus maze (EPM). Results. Chronic stress induced by MSDL affected individuals' behaviour, their behavioural profile varying according to their gender. Males exhibited more anxious behaviour than females who engaged in more locomotive and exploratory activity. Conclusions. MSDL animals' behavioural repertoire varied due to the allopregnanolone injection, suggesting that the effect of allopregnanolone due to GABA-A receptor interaction could reverse the effects of maternal separation on anxiety-related behaviour.

Phasic and Tonic Inhibition are Maintained Respectively by CaMKII and PKA in the Rat Visual Cortex

Phasic and tonic gamma-aminobutyric acid(A) (GABA(A)) receptor-mediated inhibition critically regulate neuronal information processing. As these two inhibitory modalities have distinctive features in their receptor composition, subcellular localization of receptors, and the timing of receptor activation, it has been thought that they might exert distinct roles, if not completely separable, in the regulation of neuronal function. Inhibition should be maintained and regulated depending on changes in network activity, since maintenance of excitation-inhibition balance is essential for proper functioning of the nervous system. In the present study, we investigated how phasic and tonic inhibition are maintained and regulated by different signaling cascades. Inhibitory postsynaptic currents were measured as either electrically evoked events or spontaneous events to investigate regulation of phasic inhibition in layer 2/3 pyramidal neurons of the rat visual cortex. Tonic inhibition was assessed as changes in holding currents by the application of the GABA(A) receptor blocker bicuculline. Basal tone of phasic inhibition was maintained by intracellular Ca2+ and Ca2+/calmodulin-dependent protein kinase II (CaMKII). However, maintenance of tonic inhibition relied on protein kinase A activity. Depolarization of membrane potential (5 min of 0 mV holding) potentiated phasic inhibition via Ca2+ and CaMKII but tonic inhibition was not affected. Thus, phasic and tonic inhibition seem to be independently maintained and regulated by different signaling cascades in the same cell. These results suggest that neuromodulatory signals might differentially regulate phasic and tonic inhibition in response to changes in brain states.

Single Nucleotide Polymorphisms of GABRG2 in Idiopathic Generalized Epilepsies(IGEs)

PURPOSE: Mutations in gamma-aminobutyric acid(GABA) A receptor gamma2 subunit gene (GABRG2) were independently identified in families of generalized epilepsy with febrile seizures plus(GEFS+) and families of absence epilepsy and febrile seizures(FSs). The present study assessed the role of GABRG2 gene in idiopathic generalized epilepsies(IGEs) of Korean population. METHODS: Twenty-three IGEs and 94 healthy control subjects were selected through a collaborative study of Catholic Child Neurology Research Group. The SNP211037 of GABRG2 were screened by DHPLC. DNA fragments showing variant chromatograms were subsequently sequenced. Genotypes and allelic frequencies for GABRG2 gene polymorphism in three groups were compared. RESULTS: Genotypes and allelic frequencies of the gamma2 subunit of the GABA receptor gene(SNP211037) in both groups were not significantly different. The most common genotypes for GABRG2(SNP211037) gene in both groups were T/C heterozygote. The allele C and T frequencies for GABRG2(SNP211037) in the IGEs group were 45.7% and 54.3%, respectively and in healthy control group, 42.6% and 57.4%, respectively. The number of individuals with the GABRG2 (SNP211037)-C/C genotype in the IGEs group was greater compared with that in the healthy control group(21.7% versus 12.8%). The odds ratio for developing IGEs in individuals with the GABRG2 (SNP211037)-CC genotype was 1.65 compared with individuals with the GABRG2 (SNP211037)-T/T genotype, which was not significantly different. CONCLUSION: These data suggest that genomic variations of GABRG2 might not be one of the susceptibility factors for IGEs in the Korean population.

Association between Alcoholism and the Genetic Polymorphisms of the GABA(A) Receptor Genes on Chromosome 5q33-34 in Korean Population

Family, twin, and adoption studies have demonstrated that genes play an important role in the development of alcoholism. We investigated the association between alcoholism and the genetic polymorphisms of the GABA(A) receptor genes on chromosome 5q33-34 in Korean population. The genotype of the GABA(A) receptor gene polymorphisms were determined by performing polymerase chain reaction genotyping for 172 normal controls and 162 male alcoholics who are hospitalized in alcoholism treatment institute. We found a significant association between the genetic polymorphisms of the GABA(A) alpha1 and GABA(A) alpha6 receptor gene and alcoholism. The GG genotype of the GABA(A) alpha1 receptor gene was associated with the onset age of alcoholism and alcohol withdrawal symptoms, and a high score on the Korean version of the ADS. However, there was no association between the genetic polymorphisms of the GABA(A) beta2 and gamma2 receptor gene and alcoholisms. Our finding suggest that genetic polymorphisms of the GABA(A) alpha1 and GABA(A) alpha6 receptor gene may be associated with the development of alcoholism and that the GG genotype of the GABA(A) alpha1 receptor gene play an important role in the development of the early onset and the severe type of alcoholism.

Partial mediation of GABA_A receptor in the antinociceptive stimulation of propofol at spinal level in rats / 中国药理学通报

Aim To observe the effects of propofol at spinal level on nociceptive response in rats and the possible role of GABA_A receptor.Methods In the praxiology test,Sprague-Dawley(SD) female rats were randomized into groups.Bicuculline and propofol were microinjected into intrathecally(ith).The noxious response was evaluated with hot plate and formalin test.In immunohistochemistry test,Fos-like immunoreactivity(FLI) neurons expressed in spinal dorsal horn(DH) induced by formalin intraplantar injection(sc) of one hindpaw were used as a neuroactive marker to observe the effects of propofol on the noxious transmission in DH.Results In hot-plate test,significant analgesia produced by propofol(10 g?L~(-1)) was antagonized about 81%,55%,81% and 97% at 10,20,30 and 40 min by ith bicuculline(0.01 g?L~(-1),P

Relationship between the protective effect of sodium oxybate on neuronal damage induced by hypoxia-reoxygenation and GABA_A receptor in primary cultured rat cortical neurons / 中国临床药理学与治疗学

AIM: To investigate the relationship between the protective effect of sodium oxybate on neuronal damage induced by hypoxia reoxygenation and GABA A receptor in primary cultured rat cortical neurons. METHODS: The primary cultured rat cortical neurons were used to make the hypoxia reoxygenation damage model. The morphology of cell was observed. The lactate dehydrogenase (LDH) effluxed into the media as an indicator of neuronal injury was detected after 6 h of the reoxygenation injuries. The malonyldialdehyde (MDA) contents, superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities were determined at the same time. RESULTS: The hypoxia reoxygenation caused neuronal swelling and widespread neuronal degeneration, increased LDH efflux and MDA contents, and decreased SOD and GPX activities. Sodium oxybate assuaged neuron damage, decreased LDH efflux and MDA contents (P

Enhancement effect of propofol on binding function of GABA_A receptor / 第二军医大学学报

Objective:To investigate the influence of propofol on the binding function of GABA A receptor. Methods: By using radioligand receptor binding assay, effects of propofol on the specific binding of 3H GABA and saturation curves of GABA A receptor were observed in cortical membrane preparations from mouse cerebral cortex. Results: Specific binding experiments showed that propofol at the concentrations of 10 300 ?mol/L markedly enhanced the specific binding of 3H GABA( P 0.05). Conclusion: Clinical concentrations of propofol can enhance the binding function of GABA A receptor through increasing the affinity of the low affinity binding site of GABA.

The Effect of Repeated Stress on the Modulation of Neuroactive Steroids at the GABAA-Benzodiazepine Receptor Complex in Rats / 신경정신의학

OBJECTIVES: Pregnanolone is a potent positive modulator of the gamma-aminobutyric acid(GABA) response that enhances the binding of [3H]flunitrazepam to the GABA A receptor. Recently, it was reported that chronic treatment with pregnanolone uncouples allosteric interactions between steroid and benzodiazepine recognition sites. The present study was designed to assess the effect of repeated stress on the modulation of neuroactive steroids on the GABA A receptor. METHODS: The effect of steroids on the ligands binding to GABA A receptor was investigated using cerebral cortices of unstressed and repeatedly immobilized rats. Male Sprague-Dawley rats, weighing 200-250g were forced to suffer an immobilization stress for 2 hours. RESULTS: Pregnanolone enhanced the binding of [3H]flunitrazepam to GABA A receptor in both of unstressed and repeatedly stressed rats. However, repeatedly stressed rats showed significantly higher values in EC50 and lower values in E max of enhancement binding of [3H]flunitrazepam than those of unstressed rats. CONCLUSIONS: From these findings, it can be concluded that repeated stress reduced the positive modulation of neuroactive steroid on the GABA A-receptor complex.

Expression of GABA_A receptor in hippocampal neurons and cortex in epileptic rats induced by activited hippocampal neurons products / 临床神经病学杂志

Objective To investigate the expression of GABA_A receptor in the process of activation of hippocampal neurons and explore the epileptogenesis. Methods The activated hippocampal neuron products (experiment group) and the serum-free-medium (control group) were injected into rat's lateral ventricle, respectively, then we observed the behaviors, electroencephalographic (EEG) and immunochemical changes of GABA_A receptor in rats. Results 10~30 min after administration of pentetrazole (PTZ)-activated hippocampal neuronal products, Ⅱ～Ⅲ class epileptic behaviors were found in the experiment group. EEG showed many short distance moderate amplitude sharp waves, sharp and slow wave complex. The behaviors of rats and EEG results were normal in the control group. GABA_A receptor positive cells extensively spread over cerebral cortex, hippocampal CA_1 and dentate gyrus in the control group, and the expression of GABA_A receptor significantly decreased in the experiment group.Conclusion Activated hippocampal neuronal products could induce epilepsy. One of its mechanisms might be related to the decrease of GABA_A content.

GABA_A receptor partially mediated propofol-induced hyperalgesia at ventrolateral periaqueductal gray(vlPAG) of rats / 中国药理学通报

Aim To observe the effects of propofol on nociceptive response at ventrolateral periaqueductal gray(vlPAG) of rats and the possible role of GABA_A receptor in this prosses.Methods Sprague-Dawley(SD) female rats were randomized into each group.Bicuculline and propofol were microinjected into ventrolateral periaqueductal gray(vlPAG).The noxious response was evaluated by hot plate and formalin test.Fos-like immunoreactivity(FLI) neurons expressed in spinal dorsal horn(DH) induced by formalin intraplantar injection(sc) of one hindpaw were used as a neuroactive marker to observe the effects of propofol on the noxious transmission in DH.Results In hot-plate test,the hyperalgesia induced by propofol(10 g?L~(-1)) vlPAG microinjection was significantly antagonized about(70%),(71%) at 10 and 20 min after (bicu-)culline(25 mg?L~(-1)) vlPAG microinjection(P

Modulation of AlCl_3 on GABA-activated currents in isolated rat DRG neurons / 中国药理学通报

AIM To study the modulation of AlCl 3 on GABA activated currents in isolated rat dorsal root ganglion (DRG) neurons. METHODS Using whole cell patch clamp technique to investigate the effects of AlCl 3 on GABA activated currents in isolated rat DRG neurons. RESULTS The majority of the neurons examined(46/58) were sensitive to GABA in the concentration range from 1 to 1 000 ?mol?L -1 . In the 46 GABA sensitive cells, responses induced by AlCl 3 manifested three types: (1) outward current(3/46); (2) inward current(5/46) and (3) no detectable response(38/46). As compared with GABA activated current, the amplitude of AlCl 3 activated current was smaller. Preapplication with low concentrations of AlCl 3 (≤100 ?mol?L -1 ), the GABA activated current in majority of the cells(32/38) was potentiated, which was dose dependent, the current in a few cells(4/38) was inhibited, while the remaining two(2/38) showed no effect. At higher concentration( 1 000 ?mol?L -1 ), AlCl 3 inhibited the GABA activated current( n =8). It was found that AlCl 3 potentiated both the peak value of and the steady state value of GABA activated currents. CONCLUSION AlCl 3 can modulate the function of GABA A receptors.