Effects of electroacupuncture pretreatment on GABAA receptor of fastigial nucleus and sympathetic nerve activity in rats with myocardial ischemia reperfusion injury / 中国针灸

OBJECTIVE@#To observe the effects of electroacupuncture (EA) pretreatment on cardiac function, sympathetic nerve activity, indexes of myocardial injury and GABAA receptor in fastigial nucleus in rats with myocardial ischemia reperfusion injury (MIRI), and to explore the neuroregulatory mechanism of EA pretreatment in improving MIRI.@*METHODS@#A total of 60 male SD rats were randomly divided into a sham operation group, a model group, an EA group, an agonist group and an agonist+EA group, 12 rats in each group. The MIRI model was established by ligation of the left anterior descending coronary artery. EA was applied at bilateral "Shenmen" (HT 7) and "Tongli" (HT 5) in the EA group and the agonist+EA group, with continuous wave, in frequency of 2 Hz and intensity of 1 mA, 30 min each time, once a day for 7 consecutive days. After intervention, the MIRI model was established. In the agonist group, the muscone (agonist of GABAA receptor, 1 g/L) was injected in fastigial nucleus for 7 consecutive days before modeling, 150 μL each time, once a day. In the agonist+EA group, the muscone was injected in fastigial nucleus 30 min before EA intervention. The data of electrocardiogram was collected by PowerLab standard Ⅱ lead, and ST segment displacement and heart rate variability (HRV) were analyzed; the serum levels of norepinephrine (NE), creatine kinase isoenzyme MB (CK-MB) and cardiac troponin I (cTnI) were detected by ELISA; the myocardial infarction area was measured by TTC staining; the morphology of myocardial tissue was observed by HE staining; the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were detected by immunohistochemistry and real-time PCR.@*RESULTS@#Compared with the sham operation group, in the model group, ST segment displacement and ratio of low frequency to high frequency (LF/HF) of HRV were increased (P<0.01), HRV frequency domain analysis showed enhanced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were increased (P<0.01), the percentage of myocardial infarction area was increased (P<0.01), myocardial fiber was broken and interstitial edema was serious, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were increased (P<0.01). Compared with the model group, in the EA group, ST segment displacement and LF/HF ratio were decreased (P<0.01), HRV frequency domain analysis showed reduced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were decreased (P<0.01), the percentage of myocardial infarction area was decreased (P<0.01), myocardial fiber breakage and interstitial edema were lightened, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were decreased (P<0.01). Compared with the EA group, in the agonist group and the agonist+EA group, ST segment displacement and LF/HF ratio were increased (P<0.01), HRV frequency domain analysis showed enhanced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were increased (P<0.01), the percentage of myocardial infarction area was increased (P<0.01), myocardial fiber breakage and interstitial edema were aggravated, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were increased (P<0.01).@*CONCLUSION@#EA pretreatment can improve the myocardial injury in MIRI rats, and its mechanism may be related to the inhibition of GABAA receptor expression in fastigial nucleus, thereby down-regulating the excitability of sympathetic nerve.

Avaliação in silico da atividade ansiolítica de compostos do extrato de camomila (Matricaria recutita) nos receptores GABAa humanos / In silico evaluation of the anxiolytic activity of compounds from chamomile (Matricaria recutita) extract in human GABAa receptors

Objetivo: Avaliar a possível atividade ansiolítica de compostos presentes no extrato padronizado de camomila por meio da interação com o receptor GABAa, como também analisar parâmetros farmacocinéticos das moléculas escolhidas por meio de ferramentas computacionais. Método: Simulação da interação proteína-ligante da apigenina, alfa-bisabolol e camazuleno, por meio de docagem molecular com o receptor GABAa, comparadas com diazepam. Por fim, os parâmetros farmacocinéticos dos três compostos foram calculados, usando a ferramenta on line SwissADME. Resultados: Alfa-bisabolol e camazuleno adequaram-se aos parâmetros farmacocinéticos favoráveis, enquanto a apigenina e o diazepam não atenderam ao perfil de ideal de biodisponibilidade. No estudo docking, as energias de ligação obtidas foram de -5-1 (a-bisabolol), -7,0 (camazuleno), -7,5 (diazepam), e -8.3 kcal/mol (apigenina); também foram observadas ligações do tipo hidrofóbicas, de Van der Waals e interações eletrostáticas. Conclusão: Os parâmetros analisados sugerem a atividade ansiolítica das moléculas estudas. Ademais, mais pesquisas in vivo devem ser realizadas a fim de elucidar os resultados e seus mecanismos e possíveis limitações em humanos.

Objective: To evaluate the possible anxiolytic activity of compounds present in standardized chamomile extract through interaction with the GABAa receptor and to analyze pharmacokinetic parameters of the chosen molecules through computational tools. Methods: Simulation of the protein-ligand interaction of apigenin, alpha-bisabolol, and camazulene by molecular docking with the GABAa receptor compared with diazepam. Finally, the pharmacokinetic parameters of the compounds were calculated using the SwissADME online tool. Results: Alpha-bisabolol and camazulene fit the favorable pharmacokinetic parameters, while apigenin and diazepam did not meet the ideal bioavailability profile. In the docking study. The binding energies obtained were -5-1 ( a-bisabolol), -7.0 (camazulene), -7.5 (diazepam), and -8.3 kcal/mol (apigenin). Hydrophobic bonds, Van der Waals and electrostatic interactions were observed. Conclusion: The parameters analyzed suggest an anxiolytic activity of the molecules studied. Also, more in vivo research to elucidate the results and their human and possible resources used in humans

Noradrenaline modulates the spontaneous firing activities of Purkinje cells via α2-adrenergic receptor in mouse cerebellar cortex / 生理学报

Cerebellar Purkinje cells (PCs) exhibit two types of discharge activities: simple spike (SS) and complex spike (CS). Previous studies found that noradrenaline (NA) can inhibit CS and bidirectionally regulate SS, but the enhancement of NA on SS is overwhelmed by the strong inhibition of excitatory molecular layer interneurons. However, the mechanism underlying the effect of NA on SS discharge frequency is not clear. Therefore, in the present study, we examined the mechanism underlying the increasing effect of NA on SS firing of PC in mouse cerebellar cortex in vivo and in cerebellar slice by cell-attached and whole-cell recording technique and pharmacological methods. GABAA receptor was blocked by 100 µmol/L picrotoxin in the whole process. In vivo results showed that NA significantly reduced the number of spikelets of spontaneous CS and enhanced the discharge frequency of SS, but did not affect the discharge frequency of CS. In vitro experiments showed that NA reduced the number of CS spikelets and after hyperpolarization potential (AHP) induced by electrical stimulation, and increased the discharge frequency of SS. NA also reduced the amplitude of excitatory postsynaptic current (EPSC) of parallel fiber (PF)-PC and significantly increased the paired-pulse ratio (PPR). Application of yohimbine, an antagonist of α2-adrenergic receptor (AR), completely eliminated the enhancing effect of NA on SS. The α2-AR agonist, UK14304, also increased the frequency of SS. The β-AR blocker, propranolol, did not affect the effects of NA on PC. These results suggest that in the absence of GABAA receptors, NA could attenuate the synaptic transmission of climbing fiber (CF)-PC via activating α2-AR, inhibit CS activity and reduce AHP, thus enhancing the SS discharge frequency of PC. This result suggests that NA neurons of locus coeruleus can finely regulate PC signal output by regulating CF-PC synaptic transmission.

Phytohormone abscisic acid boosts pentobarbital-induced sleep through activation of GABA-A, PPARß and PPARγ receptor signaling / O fito-hormônio ácido abscísico estimula o sono induzido por fenobarbital por meio de ativação da sinalização de receptores GABA-A, PPARß e PPARγ

ABSTRACT Background: Sleep disorders induce anxiety and forgetfulness and change habits. The chemical hypnotic drugs currently used have serious side effects and, therefore, people are drawn towards using natural compounds such as plant-based healing agents. Abscisic acid (ABA) is produced in a variety of mammalian tissues and it is involved in many neurophysiological functions. Objective: To investigate the possible effect of ABA on pentobarbital-induced sleep and its possible signaling through GABA-A and PPAR (γ and β) receptors, in male Wistar rats. Methods: The possible effect of ABA (5 and 10 µg/rat, intracerebroventricularly) on sleep onset latency time and duration was evaluated in a V-maze model of sleep. Pentobarbital sodium (40 mg/kg, intraperitoneally) was injected to induce sleep 30 min after administration of ABA. PPARβ (GSK0660, 80 nM/rat), PPARγ (GW9662, 3 nM/rat) or GABA-A receptor (bicuculline, 6 µg/rat) antagonists were given 15 min before ABA injection. Diazepam (2 mg/kg, intraperitoneally) was used as a positive control group. Results: ABA at 5 µg significantly boosted the pentobarbital-induced subhypnotic effects and promoted induction of sleep onset in a manner comparable to diazepam treatment. Furthermore, pretreatment with bicuculline significantly abolished the ABA effects on sleep parameters, while the amplifying effects of ABA on the induction of sleep onset was not significantly affected by PPARβ or PPARγ antagonists. The sleep prolonging effect of ABA was significantly prevented by both PPAR antagonists. Conclusions: The data showed that ABA boosts pentobarbital-induced sleep and that GABA-A, PPARβ and PPARγ receptors are, at least in part, involved in ABA signaling.

RESUMO Introdução: Os distúrbios do sono induzem a ansiedade e esquecimento e mudam hábitos. Os medicamentos hipnóticos químicos utilizados atualmente têm efeitos colaterais graves e, portanto, as pessoas são atraídas para o uso de compostos naturais, como agentes de cura à base de plantas. O ácido abscísico (ABA) é produzido em uma variedade de tecidos de mamíferos e está envolvido em muitas funções neurofisiológicas. Objetivo: Investigar o possível efeito do ABA no sono induzido por pentobarbital e sua possível sinalização por meio dos receptores GABA-A e PPAR (γ e β), em ratos Wistar machos. Métodos: O possível efeito do ABA (5 e 10 µg/rato, intracerebroventricularmente) no tempo de latência e duração do início do sono foi avaliado em um modelo de labirinto em V de sono. Pentobarbital sódico (40 mg/kg, intraperitonealmente) foi injetado para induzir o sono 30 minutos após a administração de ABA. PPARβ (GSK0660, 80 nM/rato), PPARγ (GW9662, 3 nM/rato) ou antagonistas do receptor GABA-A (bicuculina, 6 µg/rato) foram administrados 15 minutos antes da injeção de ABA. Diazepam (2 mg/kg, intraperitonealmente) foi utilizado como grupo de controle positivo. Resultados: ABA a 5 µg aumentou significativamente os efeitos sub-hipnóticos induzidos por pentobarbital e promoveu a indução do início do sono de forma comparável ao tratamento com diazepam. Além disso, o pré-tratamento com bicuculina aboliu significativamente os efeitos do ABA nos parâmetros do sono, ao passo que os efeitos amplificadores do ABA na indução do início do sono não foram significativamente afetados pelos antagonistas do PPARβ ou PPARγ. O efeito de prolongamento do sono do ABA foi significativamente prevenido por ambos os antagonistas do PPAR. Conclusões: Os dados mostraram que o ABA estimula o sono induzido por pentobarbital e que os receptores GABA-A, PPARβ e PPARγ estão, pelo menos em parte, envolvidos na sinalização ABA.

Effect of etomidate on the reuniens neuronal activity / 中南大学学报(医学版)

OBJECTIVES@#To explore the effect of etomidate on the neuronal activity of ventral thalamic reuniens nucleus and the underlying mechanisms.@*METHODS@#Whole-cell patch clamp method was used to explore the effect of etomidate on the activity of ventral thalamic reuniens neurons in the acute brain slices obtained from 4-5 weeks old C57BL/6J mice. The electrophysiological characteristics of ventral thalamic reuniens neurons were recorded in the current clamp mode, and then the effects of etomidate (0.5, 2.0, 8.0 μmol/L etomidate groups) and intralipid (intralipid group) on the discharge frequency and membrane potential of ventral thalamic reuniens neurons were recorded. During the experiment, the ventral thalamic reuniens neuron firing rates (RNFRs) were recorded as F@*RESULTS@#In the intralipid group, there was no significant difference among the F@*CONCLUSIONS@#Etomidate can inhibit the activity of ventral thalamic reuniens neurons in concentration-dependent manner, and which is reversible. Etomidate with sub-anesthetic concentration inhibits the activity of ventral thalamic reuniens neurons via targeting the GABA

Treatment with zolpidem after ethanol administration potentiates the expression of ethanol-induced behavioral sensitization in mice

Contradictory findings suggest that the behavioral and abuse-related effects of ethanol are mediated by its action at α1 subunit-containing GABAA (α1GABAA) receptors. In the present study, we investigated the effects of a sub-chronic post-ethanol administration treatment with zolpidem, an α1-preferring positive allosteric modulator at GABAA receptors, on the subsequent expression of ethanol-induced behavioral sensitization in mice. Animals received ethanol (1.8 g/kg, ip) or saline treatments every other day for 15 days (8 treatment sessions) and were subsequently treated with zolpidem (0.5 mg/kg, ip) or vehicle 4 times on alternate days. At the end of the treatment phase, animals were challenged with saline or ethanol on separate days for the evaluation of the expression of conditioned locomotion and behavioral sensitization. Eight-day treatment with ethanol did not lead to the development of ethanol-induced behavioral sensitization. Animals treated with ethanol and subsequently administered vehicle showed similar locomotion frequencies during the last ethanol challenge compared to the control group receiving ethanol for the first time. Animals treated with ethanol and subsequently administered zolpidem expressed behavioral sensitization to ethanol during the ethanol challenge. The present study adds to the literature by providing further evidence of a role of α1GABAA receptors on the behavioral effects of ethanol. Because of the current highly prevalent co-abuse of ethanol and benzodiazepine drugs in humans, the use of zolpidem and other α1GABAA receptor ligands during ethanol withdrawal should be monitored carefully.

Na-K-2Cl symporter contributes to γ-aminobutyric acid-evoked excitation in rat enteric neurons / 生理学报

Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the adult central nervous system (CNS), however, it causes excitation in the immature CNS neurons. The shift from GABA-induced depolarization to hyperpolarization in postnatal brain is primarily due to progressive decrease in the expression of the Na-K-2Cl symporter 1 (NKCC1) and increased expression of the K-Cl cotransporter 2 (KCC2). Unlike CNS neurons, both immature and mature neurons in the enteric nervous system (ENS) are depolarized by GABA. Molecular mechanisms by which GABA excites ENS neurons are unclear. It is understood, however, that the excitatory action depends on elevated intraneuronal Cl. We aimed to test a hypothesis that high intracellular Cl in ENS neurons is maintained by activity of the NKCCs. We found that NKCC2 immunoreactivity (IR) was expressed in the ENS of the rat colon on postnatal day 1 (P1). The expression level of NKCC2 continuously increased and reached a steady high level on P14 and maintained at that level in adulthood. NKCC1 IR appeared in ENS on P14 and maintained through adulthood. KCC2 IR was not detectable in the ENS in any of the developmental stages. Both NKCC1 IR and NKCC2 IR were co-expressed with GABA receptors in ENS neurons. Exogenous GABA (1 mmol/L) caused membrane depolarization in the ENS neurons. The reversal potential of GABA-induced depolarization was about -16 mV. Blockade of NKCC by bumetanide (50 μmol/L) or furosemide (300 μmol/L) suppressed the depolarizing responses to GABA. Bumetanide (50 μmol/L) shifted the reversal potential of GABA-induced depolarization in the hyperpolarizing direction. Neither the KCC blocker DIOA (20 μmol/L) nor the Cl/HCO exchanger inhibitor DIDS (200 μmol/L) suppressed GABA-evoked depolarization. The results suggest that ENS neurons continuously express NKCC2 since P1 and NKCC1 since P14, which contribute to the accumulation of Cl in ENS neurons and GABA-evoked depolarization in neonate and adult ENS neurons. These results provide the first direct evidence for the contribution of both NKCC2 and NKCC1 to the GABA-mediated depolarization.

Avaliação in silico da interação entre o receptor GABAA e metalocompostos derivados de benzodiazepínicos / Evaluation of the interaction between GABAA receptor and organometallics derived from benzodiazepines in silico

O receptor do ácido γ-aminobutírico do tipo A (GABAA) é o receptor de ação rápida mais amplamente distribuído no sistema nervoso central (SNC) dos mamíferos. Os receptores GABAA são canais iônicos pentaméricos transmembranares e apresentam alta heterogeneidadede entre suas subunidades. Quando estes receptores são ativados pelo neurotransmissor GABA, permitem a passagem de íons cloreto para dentro dos neurônios, resultando em uma hiperpolarização destas células, as tornando menos reativas a neurotransmissores excitatórios. Os receptores GABAA são alvos de vários grupos farmacológicos com propriedades anestésicas e sedativas. A ativação destes receptores pode ser modulada por diferentes grupos de compostos, incluindo os benzodiazepínicos (BZDs), que se tornaram o grupo farmacológico prescrito mais consumido no mundo, sendo indicados no tratamento de ansiedade, insônia, relaxamento muscular e epilepsia. Apesar de serem indicados no tratamento em diversas manifestações clínicas, podem apresentar efeitos adversos, como comprometimento da memória, síndrome de descontinuação, além da sua ineficiência no tratamento em alguns casos de epilepsia. Nesse contexto, é importante identificar e desenvolver novos compostos que apresentem as mesmas características e eficiência dos BZDs clássicos, porém minimizando seus efeitos adversos.

Uma abordagem interessante é a síntese de compostos de coordenação, a partir da associação entre compostos orgânicos com elementos metálicos a partir dos BZDs clássicos, como o diazepam. Neste trabalho, foi analisada a interação do receptor GABAA com cinco compostos de coordenação derivados do diazepam com íon paládio ([(DZP)PdOAcPPh3], [(DZP)PdClPPh3], [(DZP)PdClPy], ([(DZP)PdCl]2 e [(DZP)PdOAc]2) em um modelo heteropentamérico da principal combinação de isoformas do receptor GABAA (α1ß2γ2) construído pela técnica de modelagem comparativa. Com o intuito de predizer a pose dos ligantes, foram realizadas simulações de docking molecular entre os compostos de coordenação e o diazepam com o receptor GABAA, utilizando o software AutoDock. Nossos resultados indicam que os compostos de coordenação apresentaram energia livre de ligação estimada mais baixa que o ligante diazepam, com destaque para o composto o [(DZP)PdOAc]2. Foram identificados quatro resíduos que aparentemente contribuem para a interação proteína-ligante: His101(α1), Ser204(α1), Tyr58(γ2) e Phe77(γ2). O metal paládio incluso nos compostos de coordenação apresentou um papel de estabilidade estrutural, conferindo um maior número de interações com o receptor GABAA no sítio dos benzodiazepínicos. (AU)

Kir2.1 Channel Regulation of Glycinergic Transmission Selectively Contributes to Dynamic Mechanical Allodynia in a Mouse Model of Spared Nerve Injury / 神经科学通报·英文版

Neuropathic pain is a chronic debilitating symptom characterized by spontaneous pain and mechanical allodynia. It occurs in distinct forms, including brush-evoked dynamic and filament-evoked punctate mechanical allodynia. Potassium channel 2.1 (Kir2.1), which exhibits strong inward rectification, is and regulates the activity of lamina I projection neurons. However, the relationship between Kir2.1 channels and mechanical allodynia is still unclear. In this study, we first found that pretreatment with ML133, a selective Kir2.1 inhibitor, by intrathecal administration, preferentially inhibited dynamic, but not punctate, allodynia in mice with spared nerve injury (SNI). Intrathecal injection of low doses of strychnine, a glycine receptor inhibitor, selectively induced dynamic, but not punctate allodynia, not only in naïve but also in ML133-pretreated mice. In contrast, bicuculline, a GABA receptor antagonist, induced only punctate, but not dynamic, allodynia. These results indicated the involvement of glycinergic transmission in the development of dynamic allodynia. We further found that SNI significantly suppressed the frequency, but not the amplitude, of the glycinergic spontaneous inhibitory postsynaptic currents (gly-sIPSCs) in neurons on the lamina II-III border of the spinal dorsal horn, and pretreatment with ML133 prevented the SNI-induced gly-sIPSC reduction. Furthermore, 5 days after SNI, ML133, either by intrathecal administration or acute bath perfusion, and strychnine sensitively reversed the SNI-induced dynamic, but not punctate, allodynia and the gly-sIPSC reduction in lamina IIi neurons, respectively. In conclusion, our results suggest that blockade of Kir2.1 channels in the spinal dorsal horn selectively inhibits dynamic, but not punctate, mechanical allodynia by enhancing glycinergic inhibitory transmission.

Dexmedetomidine and propofol sedation requirements in an autistic rat model / 대한마취과학회지

BACKGROUND: Autism is a challenging neurodevelopmental disorder. Previous clinical observations have suggested altered sedation requirements for children with autism. Our study aimed to test this observation experimentally in an animal model and to explore its possible mechanisms. METHODS: Eight adult pregnant female Sprague-Dawley rats were randomly divided into two groups. Four were injected with intraperitoneal sodium valproate on gestational day 12 and four were injected with normal saline. On postnatal day 28, the newborn male rats were subjected to the open-field test to confirm autistic features. Each rat was injected intraperitoneally with a single dose of propofol (50 mg/kg) or dexmedetomidine (0.2 mg/kg). The times to loss of righting reflex (LORR) and to return of righting reflex (RORR) were recorded. On the following day, all rats were re-sedated and underwent electroencephalography (EEG). Thereafter, the rats were euthanized and their hippocampal gamma-aminobutyric acid type A (GABA(A)) and glutamate N-methyl-D-aspartate (NMDA) receptor gene expressions were assessed. RESULTS: Autistic rats showed significantly longer LORR times and shorter RORR times than did the controls (median LORR times: 12.0 versus 5.0 min for dexmedetomidine and 22.0 versus 8.0 min for propofol; P < 0.05). EEG showed a low-frequency, high-amplitude wave pattern 2 min after LORR in the control rats. Autistic rats showed a high-frequency, low-amplitude awake pattern. Hippocampal GABA(A) receptor gene expression was significantly lower and NMDA gene expression was greater in autistic rats. CONCLUSIONS: This study supports the clinical observations of increased anesthetic sedative requirements in children with autism and our biochemical analyses using and glutamate receptor gene expression highlight possible underlying mechanisms.

The use of flumazenil for benzodiazepine associated respiratory depression in postanesthesia recovery: risks and outcomes / O uso de flumazenil para depressão respiratória associada ao benzodiazepínico na recuperação pós-anestésica: riscos e resultados

Abstract Background and objectives The primary aim was to determine risk factors for flumazenil administration during postanesthesia recovery. A secondary aim was to describe outcomes among patients who received flumazenil. Methods Patients admitted to the postanesthesia recovery room at a large, academic, tertiary care facility after surgery under general anesthesia from January 1, 2010, to April 30, 2015, were identified and matched to 2 controls each, by age, sex, and surgical procedure. Flumazenil was administered in the recovery phase immediately after general anesthesia, according to the clinical judgment of the anesthesiologist. Demographic, procedural, and outcome data were extracted from the electronic health record. Conditional logistic regression, accounting for the 1:2 matched-set case-control study designs, was used to assess characteristics associated with flumazenil use. Results The incidence of flumazenil administration in the postanesthesia care unit was 9.9 per 10,000 (95% CI, 8.4-11.6) general anesthetics. History of obstructive sleep apnea (Odds Ratio [OR] = 2.27; 95% CI 1.02-5.09), longer anesthesia (OR = 1.13; 95% CI 1.03-1.24 per 30 minutes), use of total intravenous anesthesia (OR = 6.09; 95% CI 2.60-14.25), and use of benzodiazepines (OR = 8.17; 95% CI 3.71-17.99) were associated with risk for flumazenil administration. Among patients who received midazolam, cases treated with flumazenil received a higher median (interquartile range) dose than controls: 3.5 mg (2.0-4.0 mg) vs. 2.0 mg (2.0-2.0 mg), respectively (p < 0.001). Flumazenil use was correlated with a higher rate of unanticipated noninvasive positive pressure ventilation, longer postanesthesia care unit stay, and increased rate of intensive care unit admissions. Conclusions Patients who required flumazenil postoperatively had received a higher dosage of benzodiazepines and utilized more postoperative health care resources. More conservative perioperative use of benzodiazepines may improve postoperative recovery and use of health care resources.

Resumo Justificativa e objetivos Determinar os fatores de risco da administração de flumazenil durante a recuperação pós-anestésica e descrever os desfechos entre os pacientes que receberam flumazenil. Métodos Os pacientes admitidos em sala de recuperação pós-anestésica de um grande centro universitário em setor terciário de cuidados pós-cirurgia sob anestesia geral entre 1° de janeiro de 2010 e 30 de abril de 2015 foram identificados e pareados com dois controles cada por idade, sexo e procedimento cirúrgico. Flumazenil foi administrado na fase de recuperação imediatamente após a anestesia geral, de acordo com a avaliação clínica do anestesiologista. Os dados demográficos, dos procedimentos e dos desfechos foram extraídos do registro eletrônico de saúde. A regressão logística condicional para os desenhos do estudo de caso-controle pareado em 1:2 foi usada para avaliar as características associadas ao uso de flumazenil. Resultados A incidência da administração de flumazenil em sala de recuperação pós-anestésica foi de 9,9 por 10.000 (95% IC: 8,4-1,6) anestesias gerais. História da apneia obstrutiva do sono (razão de chances [OR] = 2,27; IC 95%: 1,02-5,09), anestesia de longa duração (OR = 1,13; IC 95%: 1,03-1,24 por 30 minutos), uso de anestesia intravenosa total (OR = 6,09; IC de 95%: 2,60-14,25) e uso de benzodiazepínicos (OR = 8,17; IC 95%: 3,71-17,99) foram associados a risco para a administração de flumazenil. Entre os pacientes que receberam midazolam, os casos tratados com flumazenil receberam uma dose mediana mais alta (intervalo interquartil) do que os controles: 3,5 mg (2,0-4,0 mg) vs. 2,0 mg (2,0-2,0 mg), respectivamente (p < 0,001). O uso de flumazenil foi correlacionado com uma taxa maior não prevista de ventilação não invasiva com pressão positiva, permanência mais longa em sala de recuperação pós-anestésica e aumento da taxa de admissões em unidade de terapia intensiva. Conclusão Os pacientes que precisaram de flumazenil no pós-operatório receberam uma dose maior de benzodiazepínicos e usaram mais recursos de cuidados da saúde no pós-operatório. O uso mais conservador de benzodiazepínicos no período perioperatório pode melhorar a recuperação e o uso de recursos de cuidados da saúde no pós-operatório.

GABA Receptor Activity Suppresses the Transition from Inter-ictal to Ictal Epileptiform Discharges in Juvenile Mouse Hippocampus / 神经科学通报·英文版

Exploring the transition from inter-ictal to ictal epileptiform discharges (IDs) and how GABA receptor-mediated action affects the onset of IDs will enrich our understanding of epileptogenesis and epilepsy treatment. We used Mg-free artificial cerebrospinal fluid (ACSF) to induce epileptiform discharges in juvenile mouse hippocampal slices and used a micro-electrode array to record the discharges. After the slices were exposed to Mg-free ACSF for 10 min-20 min, synchronous recurrent seizure-like events were recorded across the slices, and each event evolved from inter-ictal epileptiform discharges (IIDs) to pre-ictal epileptiform discharges (PIDs), and then to IDs. During the transition from IIDs to PIDs, the duration of discharges increased and the inter-discharge interval decreased. After adding 3 μmol/L of the GABA receptor agonist muscimol, PIDs and IDs disappeared, and IIDs remained. Further, the application of 10 μmol/L muscimol abolished all the epileptiform discharges. When the GABA receptor antagonist bicuculline was applied at 10 μmol/L, IIDs and PIDs disappeared, and IDs remained at decreased intervals. These results indicated that there are dynamic changes in the hippocampal network preceding the onset of IDs, and GABA receptor activity suppresses the transition from IIDs to IDs in juvenile mouse hippocampus.

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.

Assessment of Switching to Suvorexant versus the Use of Add-on Suvorexant in Combination with Benzodiazepine Receptor Agonists in Insomnia Patients: A Retrospective Study

OBJECTIVE: Suvorexant is a novel hypnotic drug that does not interact with the conventional γ-aminobutyric acid (GABA)-A receptor. We investigated the method by which suvorexant was introduced in insomnia patients who were taking benzodiazepine receptor agonists (BzRA). METHODS: This was a retrospective study. We extracted clinical data for patients who were prescribed suvorexant and were already using BzRA. The patients were assigned to two groups, the switching and add-on groups. We assessed the suvorexant discontinuation rate at one month after the prescription of the drug. RESULTS: One hundred and nineteen patients were assigned to the switching group, and 109 were assigned to the add-on group. The add-on group exhibited a significantly higher all-cause discontinuation rate than the switching group (odds ratio, 2.7; 95% confidence interval, 1.5 to 5.0; adjusted p < 0.001). Intolerability was a significantly stronger risk factor for suvorexant discontinuation in the add-on group (22.0% vs. 7.6%, p < 0.002), and the most common adverse effect was oversedation. CONCLUSION: Our results show that the add-on of suvorexant increases the frequency of oversedation compared with switching in insomnia patients that are taking BzRA. However, this was only a preliminary retrospective study, and further studies will be required to confirm our findings.

Regional difference in spontaneous firing inhibition by GABA(A) and GABA(B) receptors in nigral dopamine neurons

GABAergic control over dopamine (DA) neurons in the substantia nigra is crucial for determining firing rates and patterns. Although GABA activates both GABA(A) and GABA(B) receptors distributed throughout the somatodendritic tree, it is currently unclear how regional GABA receptors in the soma and dendritic compartments regulate spontaneous firing. Therefore, the objective of this study was to determine actions of regional GABA receptors on spontaneous firing in acutely dissociated DA neurons from the rat using patch-clamp and local GABA-uncaging techniques. Agonists and antagonists experiments showed that activation of either GABA(A) receptors or GABA(B) receptors in DA neurons is enough to completely abolish spontaneous firing. Local GABA-uncaging along the somatodendritic tree revealed that activation of regional GABA receptors limited within the soma, proximal, or distal dendritic region, can completely suppress spontaneous firing. However, activation of either GABA(A) or GABA(B) receptor equally suppressed spontaneous firing in the soma, whereas GABA(B) receptor inhibited spontaneous firing more strongly than GABA(A) receptor in the proximal and distal dendrites. These regional differences of GABA signals between the soma and dendritic compartments could contribute to our understanding of many diverse and complex actions of GABA in midbrain DA neurons.

A prescrição de benzodiazepínicos no Brasil: uma análise da literatura / The prescription of benzodiazepines in Brazil: a literature review

Benzodiazepínicos são medicamentos psicotrópicos de prescrição restrita e sujeitos a controle especial, conforme a Portaria nº 344, de 12 de maio de 1998. São utilizados como hipnóticos e sedativos, sendo bastante comuns na prática clínica. O uso prolongado destes fármacos pode causar dependência e por isso é necessário identificar seu perfil de prescrição. Este estudo busca revisar a literatura sobre os trabalhos que descreveram o uso de benzodiazepínicos no Brasil. Para isso, uma busca direta foi realizada em três bases de dados, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), PubMed e Scientific Eletronic Library Online (SciELO), utilizando os descritores prescrição/prescription, benzodiazepínicos/benzodiazepines, Brasil/Brazil. Depois de aplicados os critérios de inclusão e exclusão, restaram 12 artigos, os quais foram analisados. A análise destes trabalhos mostrou que, no Brasil, os benzodiazepínicos são utilizados especialmente por mulheres com tendência ao aumento do uso com o avançar da idade. Desta maneira, conclui-se que permanece a necessidade de políticas públicas que busquem o uso racional destes fármacos.

Benzodiazepines are prescription restricted psychotropic drugs, subject to special control according to Decree nº 344 of May 12, 1998. They are used as hypnotics and sedatives, being widely used in clinical practice. Prolonged use of these drugs can cause dependence, and therefore it is necessary to identify their prescription profile. This study aims to review the literature on studies that described the use of benzodiazepines in Brazil. For such, a direct search was conducted in databases, such as LILACS, Pubmed and SciELO, with the descriptors, in Portuguese and English, "prescrição" (prescription), "benzodiazepínicos" (benzodiazepines) and "Brasil" (Brazil). After applying the criteria for inclusion and exclusion, 12 articles remained, which were analyzed in this work. The analysis of these data has shown that, in Brazil, benzodiazepines are used especially by women with a tendency to increased use with advancing age. On this wat, we might conclude that Brazil's needs to improve his politics to promote rational use of Benzodiazepines.

Cancer Stem Cells are Depolarized Relative to Normal Stem Cells Derived from Human Livers

ABSTRACT Introduction and aim. The inability to distinguish cancer (CSCs) from normal stem cells (NSCs) has hindered attempts to identify safer, more effective therapies for hepatocellular carcinoma (HCC). The aim of this study was to document and compare cell membrane potential differences (PDs) of CSCs and NSCs derived from human HCC and healthy livers respectively and determine whether altered GABAergic innervation could explain the differences. Material and methods. Epithelial cell adhesion molecule (EpCAM) positive stem cells were isolated from human liver tissues by magnetic bead separations. Cellular PDs were recorded by microelectrode impalement of freshly isolated cells. GABAA receptor subunit expression was documented by reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence. Results. CSCs were significantly depolarized (-7.0 ± 1.3 mV) relative to NSCs (-23.0 ± 1.4 mV, p < 0.01). The depolarized state was associated with different GABAA receptor subunit expression profiles wherein phasic transmission, represented by GAGAA α3 subunit expression, was prevalent in CSCs while tonic transmission, represented by GABAA α6 subunit expression, prevailed in NSCs. In addition, GABAA subunits α3, β3, γ3 and δ were strongly expressed in CSCs while GABAA π expression was dominant in NSCs. CSCs and NSCs responded similarly to GABAA receptor agonists (ΔPD: 12.5 ± 1.2 mV and 11.0 ± 3.5 mV respectively). Conclusion. The results of this study indicate that CSCs are significantly depolarized relative to NSCs and these differences are associated with differences in GABAA receptor subunit expression. Together they provide new insights into the pathogenesis and possible treatment of human HCC.

Monoterpenoids (thymol, carvacrol and S-(+)-linalool) with anesthetic activity in silver catfish (Rhamdia quelen): evaluation of acetylcholinesterase and GABAergic activity

This study evaluated the anesthetic potential of thymol and carvacrol, and their influence on acetylcholinesterase (AChE) activity in the muscle and brain of silver catfish (Rhamdia quelen). The AChE activity of S-(+)-linalool was also evaluated. We subsequently assessed the effects of thymol and S-(+)-linalool on the GABAergic system. Fish were exposed to thymol and carvacrol (25, 50, 75, and 100 mg/L) to evaluate time for anesthesia and recovery. Both compounds induced sedation at 25 mg/L and anesthesia with 50-100 mg/L. However, fish exposed to carvacrol presented strong muscle contractions and mortality. AChE activity was increased in the brain of fish at 50 mg/L carvacrol and 100 mg/L thymol, and decreased in the muscle at 100 mg/L carvacrol. S-(+)-linalool did not alter AChE activity. Anesthesia with thymol was reversed by exposure to picrotoxin (GABAA antagonist), similar to the positive control propofol, but was not reversed by flumazenil (antagonist of benzodiazepine binding site), as observed for the positive control diazepam. Picrotoxin did not reverse the effect of S-(+)-linalool. Thymol exposure at 50 mg/L is more suitable than carvacrol for anesthesia in silver catfish, because this concentration did not cause any mortality or interference with AChE activity. Thymol interacted with GABAA receptors, but not with the GABAA/benzodiazepine site. In contrast, S-(+)-linalool did not act in GABAA receptors in silver catfish.

Rosmarinic Acid Potentiates Pentobarbital-Induced Sleep Behaviors and Non-Rapid Eye Movement (NREM) Sleep through the Activation of GABA(A)-ergic Systems

It has been known that RA, one of major constituents of Perilla frutescens which has been used as a traditional folk remedy for sedation in oriental countries, shows the anxiolytic-like and sedative effects. This study was performed to know whether RA may enhance pentobarbital-induced sleep through γ-aminobutyric acid (GABA)(A)-ergic systems in rodents. RA (0.5, 1.0 and 2.0 mg/kg, p.o.) reduced the locomotor activity in mice. RA decreased sleep latency and increased the total sleep time in pentobarbital (42 mg/kg, i.p.)-induced sleeping mice. RA also increased sleeping time and number of falling sleep mice after treatment with sub-hypnotic pentobarbital (28 mg/kg, i.p.). In electroencephalogram (EEG) recording, RA (2.0 mg/kg) not only decreased the counts of sleep/wake cycles and REM sleep, but also increased the total and NREM sleep in rats. The power density of NREM sleep showed the increase in δ-waves and the decrease in α-waves. On the other hand, RA (0.1, 1.0 and 10 μg/ml) increased intracellular Cl− influx in the primary cultured hypothalamic cells of rats. RA (p.o.) increased the protein expression of glutamic acid decarboxylase (GAD(65/67) ) and GABA(A) receptors subunits except β1 subunit. In conclusion, RA augmented pentobarbital-induced sleeping behaviors through GABA(A)-ergic transmission. Thus, it is suggested that RA may be useful for the treatment of insomnia.

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.