Exploration of antidepressant effect and mechanism of icariside Ⅱ based on GABAergic nervous system / 中国药房

OBJECTIVE To explore the antidepressant effect and potential mechanism of icariside Ⅱ （ICSⅡ） based on the GABAergic nervous system. METHODS The male Kunming mice were randomly divided into a control group （group C， 10 mice） and a modeling group （50 mice）. The depression model was induced by chronic unpredictable mild stress （CUMS） method in the modeling group. After 21 days of stimulation， the rats of modeling group were randomly divided into depression model group （NS group）， positive control group [ECS group， oxalate escitalopram 15 mg/（kg·d）] and ICSⅡ low-dose， medium-dose and high-dose groups [ICSⅡ-L group， ICSⅡ-M group， ICSⅡ-H group； ICSⅡ 10， 20， 30 mg/（kg·d）]， with 10 mice in each group. Administration groups were given relevant medicine intragastrically， once a day， for 14 consecutive days. The sugar water preference rate， total exercise distance， immobility time in tail suspension and forced swimming experiments were detected in each group. The morphology of neurons and Nissl bodies in the hippocampal CA3 region were observed； the contents of γ-aminobutyric acid （GABA） and glutamic acid （Glu）， GABA/Glu ratio， and the expressions of GABAergic nervous system-related proteins （GABA A receptor α1， GABA B receptor 1， vesicular GABA transporter， glutamate decarboxylase 67， GABA membranal transporter 3） were detected in hippocampus. RESULTS Compared with group C， the sugar water preference rate and the total exercise distance significantly reduced in NS group， while the values of immobility time in the tail suspension test and forced swimming test were significantly prolonged （P＜0.05）. The morphology of neurons in the CA3 area of the hippocampus was irregular and the Nissl bodies were reduced， with a significant decrease in the number of structurally intact neurons （P＜0.05）； the content of Glu was significantly increased， while the content of GABA， GABA/Glu ratio， and the expressions of GABAergic nervous system-related proteins were significantly decreased （P＜0.05）. Compared with NS group， depression behavior in each administration group was improved， and the above indexes were mostly reversed （P＜0.05）. CONCLUSIONS ICSⅡ can improve depression behavior of depression model mice. The mechanisms may be associated with regulating the balance of GABA and Glu， increasing the synthesis， transport and release of GABA， and regulating the expressions of GABA-related receptors， so as to improve GABAergic nervous system.

The role of γ-aminobutyric acid in tumor immunity / 药学学报

italic>γ-Aminobutyric acid (GABA) is a crucial inhibitory neurotransmitter found in various cells in the human body. While the GABAergic system is typically associated with the nervous system, recent research has revealed that immune cells and tumor cells also express components of this system. In the tumor microenvironment (TME), GABA is secreted to act extracellularly on other cells. GABA is metabolized via the GABA shunt and is involved in the tricarboxylic acid (TCA) cycle by generating succinate, which can provide energy for tumor cells. Activation of GABA receptors (GABARs) is a major pathway through which GABA participates in the regulation of antitumor immune responses. The activation of GABA type A receptors (GABAARs) can inhibit the activation and proliferation of T cells, elicit anti-inflammatory macrophages, and promote tumor cell growth and migration, while activation of GABA type B receptors (GABABRs) is generally considered to inhibit cancer cell migration and induce cancer cell apoptosis. In general, receptor activation inhibits immune cells, but the effect on tumor cells varies. Additionally, the downregulation of the expression levels of GABA transporters (GATs) is involved in tumor progression. Although antagonists of GABA metabolism and drugs that act on GABA receptors are considered therapeutic drugs for tumors, there have been few clinical studies conducted on them.

Facilitation of behavioral and cortical emergence from isoflurane anesthesia by GABAergic neurons in basal forebrain / 中国药理学与毒理学杂志

OBJECTIVE To reveal the role of the basal forebrain(BF)GABAergic neurons in the regulation of isoflurane anesthesia and to elucidate the underlying neural pathways.METHODS The activity of BF GABAer-gic neurons was monitored during isoflurane anesthesia using a genetically encoded calcium indicator in Vgat-Cre mice of both sexes.The activity of BF GABAer-gic neurons was manipulated by chemogenetic and opto-genetic approaches.Sensitivity,induction time and emer-gence time of isoflurane anesthesia were estimated by righting reflex.The electroencephalogram(EEG)power and burst-suppression were monitored by EEG recording.The effects of activation of GABAergic BF-thalamic reticu-lar nucleus(TRN)pathway on isoflurane anesthesia were investigated with optogenetics.RESULTS The activity of BF GABAergic neurons was generally inhibited during isoflurane anesthesia,obviously decreased during the induction of anesthesia and gradually restored during the emergence from anesthesia.Activation of BF GABAergic neurons with chemogenetics and optogenetics promoted behavioral emergence from isoflurane anesthesia,with decreased sensitivity to isoflurane,delayed induction and accelerated emergence from isoflurane anesthesia.Optogenetic activation of BF GABAergic neurons prom-oted cortical activity during isoflurane anesthesia,with decreased EEG delta power and burst suppression ratio during 0.8%and 1.4%isoflurane anesthesia,respectively.Similar to the effects of activating BF GABAergic cell bod-ies,photostimulation of BF GABAergic terminals in the TRN also strongly promoted cortical activation and behav-ioral emergence from isoflurane anesthesia.CONCLU-SION The GABAergic neurons in the BF is a key neural substrate for general anesthesia regulation that facilitates behavioral and cortical emergence from general anesthe-sia via the BF-TRN pathway.

Activation of Cannabinoid Receptor 1 in GABAergic Neurons in the Rostral Anterior Insular Cortex Contributes to the Analgesia Following Common Peroneal Nerve Ligation / 神经科学通报·英文版

The rostral agranular insular cortex (RAIC) has been associated with pain modulation. Although the endogenous cannabinoid system (eCB) has been shown to regulate chronic pain, the roles of eCBs in the RAIC remain elusive under the neuropathic pain state. Neuropathic pain was induced in C57BL/6 mice by common peroneal nerve (CPN) ligation. The roles of the eCB were tested in the RAIC of ligated CPN C57BL/6J mice, glutamatergic, or GABAergic neuron cannabinoid receptor 1 (CB1R) knockdown mice with the whole-cell patch-clamp and pain behavioral methods. The E/I ratio (amplitude ratio between mEPSCs and mIPSCs) was significantly increased in layer V pyramidal neurons of the RAIC in CPN-ligated mice. Depolarization-induced suppression of inhibition but not depolarization-induced suppression of excitation in RAIC layer V pyramidal neurons were significantly increased in CPN-ligated mice. The analgesic effect of ACEA (a CB1R agonist) was alleviated along with bilateral dorsolateral funiculus lesions, with the administration of AM251 (a CB1R antagonist), and in CB1R knockdown mice in GABAergic neurons, but not glutamatergic neurons of the RAIC. Our results suggest that CB1R activation reinforces the function of the descending pain inhibitory pathway via reducing the inhibition of glutamatergic layer V neurons by GABAergic neurons in the RAIC to induce an analgesic effect in neuropathic pain.

Bi-directional Control of Synaptic Input Summation and Spike Generation by GABAergic Inputs at the Axon Initial Segment / 神经科学通报·英文版

Differing from other subtypes of inhibitory interneuron, chandelier or axo-axonic cells form depolarizing GABAergic synapses exclusively onto the axon initial segment (AIS) of targeted pyramidal cells (PCs). However, the debate whether these AIS-GABAergic inputs produce excitation or inhibition in neuronal processing is not resolved. Using realistic NEURON modeling and electrophysiological recording of cortical layer-5 PCs, we quantitatively demonstrate that the onset-timing of AIS-GABAergic input, relative to dendritic excitatory glutamatergic inputs, determines its bi-directional regulation of the efficacy of synaptic integration and spike generation in a PC. More specifically, AIS-GABAergic inputs promote the boosting effect of voltage-activated Na+ channels on summed synaptic excitation when they precede glutamatergic inputs by >15 ms, while for nearly concurrent excitatory inputs, they primarily produce a shunting inhibition at the AIS. Thus, our findings offer an integrative mechanism by which AIS-targeting interneurons exert sophisticated regulation of the input-output function in targeted PCs.

Activation of GABAergic neurons in the zona incerta accelerates anesthesia induction with sevoflurane and propofol without affecting anesthesia maintenance or awakening in mice / 南方医科大学学报

OBJECTIVE@#To explore the regulatory effects of GABAergic neurons in the zona incerta (ZI) on sevoflurane and propofol anesthesia.@*METHODS@#Forty-eight male C57BL/6J mice divided into 8 groups (n=6) were used in this study. In the study of sevoflurane anesthesia, chemogenetic experiment was performed in 2 groups of mice with injection of either adeno-associated virus carrying hM3Dq (hM3Dq group) or a virus carrying only mCherry (mCherry group). The optogenetic experiment was performed in another two groups of mice injected with an adeno-associated virus carrying ChR2 (ChR2 group) or GFP only (GFP group). The same experiments were also performed in mice for studying propofol anesthesia. Chemogenetics or optogenetics were used to induce the activation of GABAergic neurons in the ZI, and their regulatory effects on anesthesia induction and arousal with sevoflurane and propofol were observed; EEG monitoring was used to observe the changes in sevoflurane anesthesia maintenance after activation of the GABAergic neurons.@*RESULTS@#In sevoflurane anesthesia, the induction time of anesthesia was significantly shorter in hM3Dq group than in mCherry group (P < 0.05), and also shorter in ChR2 group than in GFP group (P < 0.01), but no significant difference was found in the awakening time between the two groups in either chemogenetic or optogenetic tests. Similar results were observed in chemogenetic and optogenetic experiments with propofol (P < 0.05 or 0.01). Photogenetic activation of the GABAergic neurons in the ZI did not cause significant changes in EEG spectrum during sevoflurane anesthesia maintenance.@*CONCLUSION@#Activation of the GABAergic neurons in the ZI promotes anesthesia induction of sevoflurane and propofol but does not affect anesthesia maintenance or awakening.

Investigating the role of Prefrontal Neurons in cognitive tasks through Fiber Photometry and Adapted Barnes Maze Protocols

The medial prefrontal cortex (mPFC) is essential in the execution of cognitive tasks, however very little is known on how these neurons are modulated during specific tasks and which subtype of neurons are responsible for so. Therego, with the intention of addressing this issue, we recorded mPFC gabaergic and glutamatergic activation patterns through fiber photometry (FIP) in mice, while simultaneously performing the Barnes Maze (BM) cognitive task (4 day behavioral trial). In addition, an altered structural and procedural protocol for BM was validated in this study due to necessary modifications allowing FIP and BM to happen simultaneously. A successful protocol validation was followed by our preliminary results, which showed that both glutamatergic and gabaergic neurons presented significant change in activation intensity and number of events in specific contexts throughout the task days. In addition, when stratified and crossed with BM performance parameters, such as latency to complete tasks and adopted strategy, glutamatergic and gabaergic neurons presented a significant decline in both activation patterns and number of activation events throughout the days. This data suggest not only an important role of glutamatergic and gabaergic mPFC neurons in learning, memory and decision making, but also that activation patterns of each of these groups may serve as markers for cognitive progression and/or dysfunction. KEY-WORDS: Memory, Learning, Decision Making, Medial Prefrontal Cortex (mPFC), Fiber Photometry (FIP), Barnes Maze (BM), Glutamatergic, Gabaergic, Neuronal Activity, Neuronal Activation Patterns, Neuronal Dynamics.

O córtex pré-frontal medial (mPFC) é essencial na execução de tarefas cognitivas, no entanto, pouco se sabe sobre como esses neurônios são modulados durante tarefas específicas e qual subtipo de neurônios é responsável por isso. Portanto, com a intenção de abordar essa questão, registramos os padrões de ativação de neurônios gabaérgicos e glutamatérgicos do mPFC por meio de fotometria de fibra (FIP) em camundongos, enquanto realizávamos simultaneamente a tarefa cognitiva do Labirinto de Barnes (BM) (ensaio comportamental de 4 dias). Além disso, um protocolo estrutural e procedimental alterado para o BM foi validado neste estudo devido a modificações necessárias que permitiram a realização simultânea de FIP e BM. Uma validação bem-sucedida do protocolo foi seguida pelos nossos resultados preliminares, que mostraram que tanto os neurônios glutamatérgicos quanto os gabaérgicos apresentaram mudanças significativas na intensidade de ativação e no número de eventos em contextos específicos ao longo dos dias da tarefa. Além disso, quando estratificados e cruzados com parâmetros de desempenho do BM, como latência para completar as tarefas e estratégia adotada, os neurônios glutamatérgicos e gabaérgicos apresentaram uma diminuição significativa nos padrões de ativação e no número de eventos de ativação ao longo dos dias. Esses dados sugerem não apenas um papel importante dos neurônios glutamatérgicos e gabaérgicos do mPFC na aprendizagem, memória e tomada de decisões, mas também que os padrões de ativação de cada um desses grupos podem servir como marcadores de progressão e/ou disfunção cognitiva. PALAVRAS-CHAVE: Memória, Aprendizagem, Tomada de Decisões, Córtex Pré-Frontal Medial (mPFC), Fotometria de Fibra (FIP), Labirinto de Barnes (BM), Glutamatérgico, Gabaérgico, Atividade Neuronal, Padrões de Ativação Neuronal, Dinâmica Neuronal.

Advances in new fast-acting antidepressants / 中国临床药理学与治疗学

Antidepressants are mainly used to treat mental illnesses. Traditional antidepressants mainly target monoamine neurotransmitters, but these drugs are slow to be effective and cannot meet clinical needs. Recently, therapeutics have been developed that depart from the traditional monoamine hypothesis and focus on the glutamatergic, GABAergic, opioidergic, and inflammatory systems. In recent years, great progress has been made in the development of new antidepressants, some of which have been applied in clinical practice. This article mainly summarizes the research mechanisms and treatment programs of new antidepressants, and briefly reviews common rapid-acting antidepressants.

Modelagem celular in vitro da Doença de Huntington com ácido 3-nitropropiônico e ácido quinolínico & Avaliação das funções neuroprotetoras da adenosina / In vitro cell modeling of Huntington's Disease with 3-nitropropionic acid and quinolinic acid and evaluation of the neuroprotective functions of adenosine

A Doença de Huntington (Huntington's disease - HD) trata-se de uma patologia neurodegenerativa hereditária caracteriza por meio da expressão das proteínas huntingtinas mutantes (mHtt), das mortes dos neurônios espinhais médios (medium spiny neurons MSNs) GABAérgicos D2-positivos do striatum e da hipercinesia. Uma hipótese se refere à função das mHtts de potencializarem os efeitos excitotóxicos das estimulações dos receptores de NMDA (NMDAR) por meio da inibição da succinato desidrogenase, resultando em desequilibrio das [Ca2+]i, estresse oxidativo e apoptose. A adenosina agonista dos receptores purinérgicos P1 tem sido descrita por conta das suas funções neuroprotetoras e neuromodulatórias. Assim, estabelecemos dois modelos in vitro da HD fundamentados nas neurodiferenciações das linhagens murinas de célula-tronco embrionárias E14-TG2a e progenitoras neurais do hipocampo HT-22; seguidas pelos tratamentos com ácido quinolínico (QA) agonista seletivo dos NMDARs , na ausência e na presença do ácido 3-nitropropiônico (3-NP) inibidor irreversível da succinato desidrogenase. Estes modelos foram utilizados nas avaliações das funções neuroprotetoras da adenosina. Os neurônios pós-mitóticos das culturas de E14-TG2a diferenciadas foram caracterizados conforme os MSNs GABAérgicos do striatum; enquanto os neurônios HT-22 diferenciados foram caracterizados de modo inespecífico. Metodologia: imunofluorescência (microscopia e citometria); PCR em tempo real; análise das variações dos potenciais das membranas plasmáticas e das variações transientes das [Ca2+]i por microfluorimetria; e quantificações das reduções do AlamarBlue® (% de sobrevida celular) e das atividades extracelulares de LDH (U/L) (necrose) por espectrometria. Avaliamos a capacidade do 3-NP de potencializar os efeitos excitotóxicos do QA comparando dois grupos de neurônios HT-22 diferenciados: QA 8mM (EC50) (controle); e 3-NP 5mM/QA 8mM. Avaliarmos o potencial neuroprotetor da adenosina comparando quatro grupos de neurônios HT-22 diferenciados: QA 8mM; adenosina 250µM/QA 8mM; 3-NP 5mM/QA 8mM; 3-NP 5mM/adenosina 250µM/QA 8mM. Os neurônios pós-mitóticos derivados das E14TG2a foram classificados como MSNsGABAérgicos do striatum integrantes de uma cultura neuronal heterogênea semelhante às conexões nigroestriatais, corticoestriatais, striatonigral e striatopallidal. Os neurônios HT-22 diferenciados perfaziam uma cultura neuronal heterogênea, não totalmente madura, composta por neurônios glutamatérgicos, dopaminérgicos, colinérgicos e GABAérgicos. Os neurônios HT-22 diferenciados 3-NP 5mM apresentaram menores % de sobrevida celular após os tratamentos com QA 8mM por 24h (p<0.05); e maiores amplitudes das variações das [Ca2+]i dependentes do QA 8mM (p<0.05) (cinética 6 minutos). Por outro lado, os neurônios HT-22 diferenciados pré- tratados com 3-NP 5mM apresentaram menores atividades extracelulares de LDH após o tratamento com QA 8mM por 24h menor proporção de necrose. Os pré-tratamentos com adenosina 250µM indicaram uma tendência dos efeitos neuroprotetores (p>0.05) maiores % de sobrevida celular; menores atividades extracelulares de LDH; e menores amplitudes das variações transientes das [Ca2+]i. Em conjunto, nossos resultados indicam que a inibição da succinato desidrogenase potencializa os efeitos excitotóxicos dos NMDARs por meio da alteração das [Ca2+]i e, provavelmente, dos mecanismos de morte celular; enquanto a adenosina apenas tendeu à neuroproteção

Huntington's disease (HD) is a hereditary neurodegenerative pathology characterized by mutant huntingtin proteins (mHtt) expression, striatum D2-positive GABAergic medium spiny neurons (MSNs) cell death and hyperkinetic motor symptoms development. One hypothesis refers to the principle that mHtt potentiates the excitotoxic effects of NMDA receptor (NMDAR) stimulation by the inhibition of mitochondrial succinate dehydrogenase, resulting in [Ca2+]i imbalance, oxidative stress and apoptosis. Adenosine P1 purinergic receptor agonist is related to neuroprotective and neuromodulatory functions. Thus, we established two in vitro HD models based on the neurodifferentiation of murine embryonic stem cell lines E14-TG2a and hippocampal neuroprogenitor cell line HT-22 followed by treatment with quinolinic acid (QA) selective agonist of NMDARs , in the absence and in the presence of 3-nitropropionic acid (3-NP) irreversible inhibitor of succinate dehydrogenase. These models were used to assess the neuroprotective functions of adenosine. Post-mitotic neurons from differentiated E14-TG2a cultures were characterized according to striatum's GABAergic MSNs; while the differentiated HT-22 neurons were characterized in a non-specific way. Methodology included immunofluorescence (microscopy and cytometry); real-time PCR; analysis of variations in the plasma membrane potentials and of transient variations in the [Ca2+]i by microfluorimetry; and quantification of AlamarBlue® reductions (% cell survival) and of extracellular LDH activity (U/L) (necrosis) by spectrometry. We evaluated the ability of 3-NP to potentiate the excitotoxic effects of QA by comparing two groups of differentiated HT-22 neurons: 8mM QA (control); and 5mM 3-NP/8mM QA. We evaluated the neuroprotective potential of adenosine comparing four groups of differentiated HT-22 neurons: QA 8mM; 250µM adenosine/8mM QA; 5mM 3-NP/8mM QA; 5mM 3-NP/250µM adenosine/8mM QA. Postmitotic neurons derived from E14TG2a were classified as striatums GABAergic MSNs that are part of a heterogeneous neuronal culture similar to nigrostriatal, corticostriatal, striatonigral, and striatopallidal connections. Differentiated HT-22 neurons consisted of a heterogeneous neuronal culture and not fully mature glutamatergic,dopaminergic, cholinergic and GABAergic neurons. Differentiated HT-22 neurons following 5mM 3-NP treatment showed lower % cell survival after treatments with 8mM QA for 24h (p<0.05); and higher amplitudes of the variations of [Ca2+]i induced by 8mM QA (p<0.05) (kinetics 6 minutes). On the other hand, differentiated HT-22 neurons 5mM 3-NP showed lower extracellular LDH activities after treatment with 8mM QA for 24h indicating a lower proportion of necrotic cells. Pretreatments with 250µM adenosine indicated a trend towards neuroprotective effects, such as higher percentages of cell survival; lower extracellular LDH activities; and lower amplitudes of transient variations of [Ca2+]i. Taken together, our results indicate that succinate dehydrogenase inhibition potentiated the excitotoxic effects of NMDARs by altering [Ca2+]i and, probably, cell death mechanisms, while adenosine only to neuroprotection

Hypothalamic hamartoma with gelastic seizures: a case report

Hypothalamic Hamartoma (HH) may have diverse clinical manifestations. Its hallmark association is with gelastic seizures. Gelastic epilepsy is characterized by episodes of loud, hollow, mirthless, stereo-typed, forced laughter. The patient may stare and giggle briefly without any other motor manifestations. Hypothalamic hamartoma is most often the cause of gelastic seizures. Here, authors report a case of gelastic seizure with hypothalamic hamartoma in a 14-month-old boy with an associated tonic clonic seizure.' This case highlights the possibility of underdiagnosed hypothalamic hamartoma in younger age groups among pediatric population.

Advances on GABAergic interneurons in autism spectrum disorders / 浙江大学学报·医学版

More and more evidences support that the abnormality of GABAergic interneurons is associated with autism spectrum disorders (ASD), epilepsy, schizophrenia and other neurodevelopmental disorders. In recent years, numerous drugs have been developed to regulate ion channels and receptors in GABAergic interneurons, including sodium channels and N-methyl-D-aspartate (NMDA) receptors. The activators of Na channel can enhance the action potential of GABAergic interneurons by reducing the inactivation of Na channel. NMDA receptor, as a potential therapeutic target of ASD, can restore the NMDA function of GABAergic interneurons, which would be used to treat behavioral defects. In addition, there are many ion channels and receptors on GABAergic interneurons related to ASD. This article reviews GABAergic interneurons in the pathogenesis of ASD and the related interventions.

Citrus limon (L.) Burm f. Essential Oil Has Anxiolytic and Sedative Properties by Modulating GABAA-Receptors

Abstract The high prevalence of anxiety disorders associated with pharmacotherapy side effects have motivated the search for new pharmacological agents. Species from Citrus genus, such as Citrus limon (sicilian lemon), have been used in folk medicine as a potential therapy to minimize emotional disorders. In order to searching for new effective treatments with fewer side effects, the present study evaluated the anxiolytic mechanism of action and the hypnotic-sedative activity from the Citrus limon fruit's peels essential oil (CLEO). Adults male Swiss mice were submitted to barbiturate-induced sleep test; elevated plus-maze (EPM) and light-dark box (LDB) (evaluation of the mechanism of action); rotarod; and catalepsy tests. CLEO oral treatment decreased latency and increased the sleep total time; moreover it induced in animals an increased the number of entries and percentage of time spent into open arms of the EPM; an increased the number of transitions and the percentage of time into light compartment in the LDB; which were only antagonized by flumazenil pretreatment, with no injury at motor function. Thus, results suggest that CLEO treatment induced an anxiolytic behavior suggestively modulated by the benzodiazepine binding site of the GABAA receptor or by an increase of GABAergic neurotransmission, without cause impairment in the motor coordination.

Preventive effects of Topiramate on methylphenidate induced behavioral disorders / Efectos preventivos de topiramato en los trastornos del comportamiento inducidos por metilfenidato

Neuronal cell damage is often caused by prolonged misuse of Methylphenidate (MPH). Topiramate (TPM) carries neuroprotective properties but its assumed mechanism remains unclear. The present study evaluates in vivo role of various doses of TPM and its mechanism against MPH-induced motor activity and related behavior disorder. Thus, we used domoic acid (DOM), bicuculline (BIC), Ketamine (KET), Yohimibine (YOH) and Haloperidole (HAL) as AMPA/kainite, GABAA, NMDA, ɑ2 adrenergic and D2 of dopamine receptor antagonists respectively. Open Field Test (OFT), Elevated Plus Maze (EPM) and Forced Swim Test (FST) were used to study motor activity, anxiety and depression level. TPM (100 and 120 mg/kg) reduced MPH-induced rise and inhibited MPH-induced promotion in motor activity disturbance, anxiety and depression. Pretreatment of animals with KET, HAL, YOH and BIC inhibited TPM- improves anxiety and depression through the interacting with Dopaminergic, GABAA, NMDA and ɑ2-adrenergic receptors.

El daño a las células neuronales a menudo es causado por el uso prolongado de metilfenidato (MPH). El topiramato (TPM) tiene propiedades neuroprotectoras, pero su mecanismo de acción no es claro. El presente estudio evalúa el papel in vivo de varias dosis de TPM y su mecanismo contra la actividad motora inducida por MPH y el trastorno de comportamiento relacionado. Utilizamos ácido domoico (DOM), bicuculina (BIC), ketamina (KET), yohimbina (YOH) y haloperidol (HAL), así como antagonistas AMPA/kainato, GABAA, NMDA, ɑ2-adrenérgico y D2 dopaminérgicos, respectivamente. Se utilizaron las pruebas de campo abierto (OFT), elevación de laberinto (EPM) y natación forzada (FST) para estudiar la actividad motora, la ansiedad y el nivel de depresión. El TPM (100 y 120 mg/kg) redujo el aumento inducido por MPH e inhibió la promoción inducida por MPH en la alteración de la actividad motora, la ansiedad y la depresión. El tratamiento previo de animales con KET, HAL, YOH y BIC inhibió el TPM, mejora la ansiedad y la depresión a través de la interacción con los receptores dopaminérgicos, GABAA, NMDA y ɑ2-adrenérgico.

Analgesic and sedative effects of Mongolian medicine Syringa pinnatifolia / 中国中药杂志

The peeled root,stem or twig of Syringa pinnatifolia is a representative Mongolian folk medicine with the effects of antidepression and pain relief. It has been used for the treatments of heart tingling,heart palpitations,upset,insomnia and other symptoms. Inspired by Mongolian medical theory and clinical practices,this study evaluated the analgesic effect of S. pinnatifolia ethanol extract( T) through three analgesic models including acetic acid writhing test,formalin test,and hot plate test,and the sedative effect of T was evaluated by locomotor activity and synergistic sleeping experiments,and furthermore the effects of T on the GABAergic nervous system were investigated by ELISA,immunohistochemistry,Western blot,and PCR methods. The results showed that T can significantly reduce the number of writhing,the time of paw licking and extend the thermal threshold of mice,suggesting the analgesic effect of T.T also can indicate its sedative effect by reducing the number of activities,decreasing latency of sleeping and extending sleeping time of mice. ELISA results showed that T can increase the content of GABA/Glu in rat cortex,hippocampus,and hypothalamus,and the most significant increase in hypothalamus. The immunohistochemistry and Western blot results showed that T can up-regulate the expression of GAD67 protein in hypothalamus,and the PCR results showed that T can up-regulate the expression of GABAA Rα1,α2,α3,α5,β1-3,γ1-3 genes,suggesting a sedative effect through the GABAergic nervous system. In conclusion,this study shed insight into the theoretical basis and clinical application of S. pinnatifolia,and also provides inspiration for subsequent development and application.

The effect of µ-opioid receptor activation on GABAergic neurons in the spinal dorsal horn

The superficial dorsal horn of the spinal cord plays an important role in pain transmission and opioid activity. Several studies have demonstrated that opioids modulate pain transmission, and the activation of µ-opioid receptors (MORs) by opioids contributes to analgesic effects in the spinal cord. However, the effect of the activation of MORs on GABAergic interneurons and the contribution to the analgesic effect are much less clear. In this study, using transgenic mice, which allow the identification of GABAergic interneurons, we investigated how the activation of MORs affects the excitability of GABAergic interneurons and synaptic transmission between primary nociceptive afferent and GABAergic interneurons. We found that a selective µ-opioid agonist, [D-Ala², NMe-Phe⁴, Gly-ol]-enkephanlin (DAMGO), induced an outward current mediated by K⁺ channels in GABAergic interneurons. In addition, DAMGO reduced the amplitude of evoked excitatory postsynaptic currents (EPSCs) of GABAergic interneurons which receive monosynaptic inputs from primary nociceptive C fibers. Taken together, we found that DAMGO reduced the excitability of GABAergic interneurons and synaptic transmission between primary nociceptive C fibers and GABAergic interneurons. These results suggest one possibility that suppression of GABAergic interneurons by DMAGO may reduce the inhibition on secondary GABAergic interneurons, which increase the inhibition of the secondary GABAergic interneurons to excitatory neurons in the spinal dorsal horn. In this circumstance, the sum of excitation of the entire spinal network will control the pain transmission.

Aucubin Promotes Differentiation of Neural Precursor Cells into GABAergic Neurons

Aucubin is a small compound naturally found in traditional medicinal herbs with primarily anti-inflammatory and protective effects. In the nervous system, aucubin is reported to be neuroprotective by enhancing neuronal survival and inhibiting apoptotic cell death in cultures and disease models. Our previous data, however, suggest that aucubin facilitates neurite elongation in cultured hippocampal neurons and axonal regrowth in regenerating sciatic nerves. Here, we investigated whether aucubin facilitates the differentiation of neural precursor cells (NPCs) into specific types of neurons. In NPCs cultured primarily from the rat embryonic hippocampus, aucubin significantly elevated the number of GAD65/67 immunoreactive cells and the expression of GAD65/67 proteins was upregulated dramatically by more than three-fold at relatively low concentrations of aucubin (0.01 µM to 10 µM). The expression of both NeuN and vGluT1 of NPCs, the markers for neurons and glutamatergic cells, respectively, and the number of vGluT1 immunoreactive cells also increased with higher concentrations of aucubin (1 µM and 10 µM), but the ratio of the increases was largely lower than GAD expression and GAD immunoreactive cells. The GABAergic differentiation of pax6-expressing late NPCs into GABA-producing cells was further supported in cortical NPCs primarily cultured from transgenic mouse brains, which express recombinant GFP under the control of pax6 promoter. The results suggest that aucubin can be developed as a therapeutic candidate for neurodegenerative disorders caused by the loss of inhibitory GABAergic neurons.

Whole-Brain Mapping of Direct Inputs to and Axonal Projections from GABAergic Neurons in the Parafacial Zone / 神经科学通报·英文版

The GABAergic neurons in the parafacial zone (PZ) play an important role in sleep-wake regulation and have been identified as part of a sleep-promoting center in the brainstem, but the long-range connections mediating this function remain poorly characterized. Here, we performed whole-brain mapping of both the inputs and outputs of the GABAergic neurons in the PZ of the mouse brain. We used the modified rabies virus EnvA-ΔG-DsRed combined with a Cre/loxP gene-expression strategy to map the direct monosynaptic inputs to the GABAergic neurons in the PZ, and found that they receive inputs mainly from the hypothalamic area, zona incerta, and parasubthalamic nucleus in the hypothalamus; the substantia nigra, pars reticulata and deep mesencephalic nucleus in the midbrain; and the intermediate reticular nucleus and medial vestibular nucleus (parvocellular part) in the pons and medulla. We also mapped the axonal projections of the PZ GABAergic neurons with adeno-associated virus, and defined the reciprocal connections of the PZ GABAergic neurons with their input and output nuclei. The newly-found inputs and outputs of the PZ were also listed compared with the literature. This cell-type-specific neuronal whole-brain mapping of the PZ GABAergic neurons may reveal the circuits underlying various functions such as sleep-wake regulation.

The Effect of 4-hydroxybenzaldehyde on the γ-aminobutyric Acid Type A Receptor

in the mammalian cortex and hippocampus. It is expressed heterologously in the Xenopus laevis oocyte as a α1β2γ2S/L subtype for application as an in vitro model for the screening of compounds that modulate receptor activities. In fact, 4-hydroxybenzaldehyde (4-HB) has been identified as one of the major components in Dendrocalamus asper bamboo shoots in our previous study, and the current study showed that at 101.7 μM, 4-HB significantly reduced the GABA-induced chloride current of GABAA receptors expressed on Xenopus oocytes, indicating a possible GABAergic antagonistic effect at high concentrations.

Human prefrontal layer II interneurons in areas 46, 10 and 24 / Interneuronas de la lámina II en las áreas prefrontales 46, 10 y 24 del humano

Background: Prefrontal cortex (PFC) represents the highest level of integration and control of psychic and behavioral states. Several dysfunctions such as autism, hyperactivity disorders, depression, and schizophrenia have been related with alterations in the prefrontal cortex (PFC). Among the cortical layers of the PFC, layer II shows a particular vertical pattern of organization, the highest cell density and the biggest non-pyramidal/pyramidal neuronal ratio. We currently characterized the layer II cytoarchitecture in human areas 10, 24, and 46. Objective: We focused particularly on the inhibitory neurons taking into account that these cells are involved in sustained firing (SF) after stimuli disappearance. Methods: Postmortem samples from five subjects who died by causes different to central nervous system diseases were studied. Immunohistochemistry for the neuronal markers, NeuN, parvalbumin (PV), calbindin (CB), and calretinin (CR) were used. NeuN targeted the total neuronal population while the rest of the markers specifically the interneurons. Results: Cell density and soma size were statically different between areas 10, 46, 24 when using NeuN. Layer II of area 46 showed the highest cell density. Regarding interneurons, PV+-cells of area 46 showed the highest density and size, in accordance to the proposal of a dual origin of the cerebral cortex. Interhemispheric asymmetries were not identified between homologue areas. Conclusion: First, our findings suggest that layer II of area 46 exhibits the most powerful inhibitory system compared to the other prefrontal areas analyzed. This feature is not only characteristic of the PFC but also supports a particular role of layer II of area 46 in SF. Additionally, known functional asymmetries between hemispheres might not be supported by morphological asymmetries.

Antecedentes: La corteza prefrontal (CPF) representa el nivel más alto de integración y control de funciones psíquicas y comportamentales. Varias patologías como autismo, desórdenes de hiperactividad, depresión y esquizofrenia se han relacionado con alteraciones de la CPF. La lámina II de las áreas que constituyen la CPF posee un patrón de organización vertical, una alta densidad celular y la mayor proporción de neuronas no-piramidal/piramidal. Sin embargo, la distribución del componente inhibitorio en estas regiones no se ha descrito. Objetivo: En el presente estudio nos propusimos caracterizar la lámina II de las áreas 10, 24 y 46 del humano, particularmente su componente inhibitorio teniendo en mente su participación en procesos de actividad sostenida relevantes cuando desaparece el estímulo. Métodos: Se utilizaron muestras de cinco sujetos que fallecieron por causas diferentes a enfermedades del sistema nervioso. Se tomaron secciones de las áreas 10, 24 y 46 de Brodmann y se procesaron con los anticuerpos contra NeuN para determinar la población neuronal total y contra Parvalbumina (PV), Calbindina (CB) y Calretinina (CR) para analizar la población de interneuronas. Resultados: Los resultados no mostraron diferencias interhemisféricas entre las áreas. Sin embargo, las tres áreas seleccionadas son significativamente diferentes entre sí en todos los parámetros analizados. El área 46 posee la mayor densidad y tamaño de interneuronas positivas para PV. Conclusiones: La ausencia de asimetrías morfológicas no permite explicar las asimetrías funcionales. La lámina II del área 46 posee el sistema inhibitorio más poderoso. Teniendo en cuenta la arquitectura modular de las capas supragranulares, este sistema inhibitorio subyace a la actividad sostenida, eje fundamental de la memoria operativa.

Antinociceptive Effect of Gabapentin In Visceral Pain is not Mediated by GABAA or Opioid Receptors.

Aims: There is evidence supporting the antinociceptive effect of gabapentin in visceral pain, however, the underlying mechanism(s) is not determined yet. So this study was performed to evaluate probable involvement of opioid and GABAergic receptors in the gabapentin effects on acetic acid-induced visceral pain in mice. Place and Duration of Study: Kerman Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran, between June 2012 and March 2013. Methodology: The acetic acid test was induced by intraperitoneal injection (i.p.) of acetic acid 0.6% (10ml/kg of body weight) in male mice. Writhing reflex was measured as the number of abdominal contractions in 45min. Animals received saline (as control) or gabapentin (1, 5, 10, 25, 50, 100 or 200mg/kg/ i.p.) 40min before acetic acid. The least effective dose of gabapentin (50mg/kg i.p.) was selected for further assessments and mice were pretreated either picrotoxin (0.75, 1 and 1.5mg/kg/i.p.) as chloridechannel blocker, bicuculline (0.5, 0.75, 1.5 and 2mg/kg) as GABAA receptor antagonist or naloxone (2mg/kg/i.p.) as opioid receptor antagonist, 10min before gabapentin (50mg/kg i.p.) treatment. Separate groups received naloxone or picrotoxin (1.5mg/kg) or bicuculline (2mg/kg) alone 10min before saline in acetic acid induced visceral contractions test. Results: Gabapentin reduced acetic acid-induced writhing in dose-dependent manner. Visceral contractions following naloxone, picrotoxin and bicuculline administration prior to gabapentin was not significantly different from that of gabapentin alone. Only toxic doses of picrotoxin and bicuculline (1.5 and 2mg/kg, respectively) abolished the inhibitory effect of gabapentin. Conclusion: The effect of gabapentin on visceral nociception is not mediated through opioid and/or GABAA receptors.