RESUMO
This study aimed to investigate the possible gamma-decanolactone mechanisms of action in the GABAergic and adenosine systems using the aminophylline-induced acute crisis model and the pentylenetetrazole-induced kindling model. In the acute model, male mice received administration of bicuculline (GABAA receptor antagonist), 8-cyclopentyl-1,3-dipropylxanthine (A1 receptor antagonist) or ZM241385 (A2A receptor antagonist), 15 min before the treatment with gamma-decanolactone (300 mg/kg). After a single dose of aminophylline was administered, the animals were observed for 60 min. In the chronic model of seizure, 30 min after the treatment with gamma-decanolactone, mice received pentylenetetrazole once every third day. On the last day of kindling, the animals received the same GABA and adenosine antagonists used in the acute model, 15 min before gamma-decanolactone administration. The protein expression of GABAA α1 receptor and adenosine A1 receptor was detected using western blotting technique in hippocampal samples. The results showed that gamma-decanolactone increased the latency to first seizure and decreased seizure occurrence in the acute and chronic models. The adenosine A2A receptor antagonist and GABAA receptor antagonist were not able to change gamma-decanolactone behavioral seizure induced by aminophylline or pentylenetetrazole. The administration of adenosine A1 receptor antagonist reversed the protective effect of gamma-decanolactone in both models. In addition, gamma-decanolactone promoted an increase in the expression GABAA α1 receptor, in the hippocampus. The results suggest that the neuroprotective effect of gamma-decanolactone observed during the investigation could have a straight connection to its action on A1 adenosine receptors.
Assuntos
Lactonas/farmacologia , Fármacos Neuroprotetores/farmacologia , Receptor A1 de Adenosina/fisiologia , Convulsões/tratamento farmacológico , Doença Aguda , Animais , Doença Crônica , Modelos Animais de Doenças , Lactonas/uso terapêutico , Masculino , Camundongos , Receptor A1 de Adenosina/efeitos dos fármacos , Receptores de GABA/fisiologiaRESUMO
Considering the involvement of GABAergic system in the action of the fast-acting antidepressant ketamine, and that agmatine may exert an antidepressant-like effect through mechanisms similar to ketamine, the purpose of the present study was to evaluate the involvement of GABAA and GABAB receptors in the antidepressant-like effect of agmatine. The administration of muscimol (0.1 mg/kg, i.p., GABAA receptor agonist) or diazepam (0.05 mg/kg, p.o., GABAA receptor positive allosteric modulator) at doses that caused no effect in the tail suspension test (TST) combined with a subeffective dose of agmatine (0.0001 mg/kg, p.o.) produced a synergistic antidepressant-like effect in the TST. In another set of experiments, the administration of baclofen (1 mg/kg, i.p., GABAB receptor agonist) abolished the reduction of immobility time in the TST elicited by agmatine (0.1 mg/kg, p.o., active dose). In another cohort of animals, treatment with NMDA (0.1 pmol/site, i.c.v.) prevented the antidepressant-like effect of the combined administration of agmatine and muscimol as well as ketamine and muscimol in the TST. Results suggest that the effect of agmatine in the TST may involve an activation of GABAA receptors dependent on NMDA receptor inhibition, similar to ketamine, as well as modulation of GABAB receptors.
Assuntos
Agmatina/uso terapêutico , Antidepressivos/uso terapêutico , Depressão/tratamento farmacológico , Neurônios GABAérgicos/efeitos dos fármacos , Receptores de GABA/fisiologia , Agmatina/farmacologia , Animais , Antidepressivos/farmacologia , Depressão/psicologia , Feminino , Agonistas GABAérgicos/farmacologia , Antagonistas GABAérgicos/farmacologia , Neurônios GABAérgicos/fisiologia , Elevação dos Membros Posteriores/efeitos adversos , Elevação dos Membros Posteriores/psicologia , Camundongos , Ácido gama-Aminobutírico/fisiologiaRESUMO
AIM: To identify genetic variants associated with greater tobacco consumption in a Mexican population. PATIENTS & METHODS: Daily smokers were classified as light smokers (LS; n = 742), heavy smokers (HS; n = 601) and nonsmokers (NS; n = 606). In the first stage, a genotyping microarray that included 347 SNPs in CHRNA2-CHRNA7/CHRNA10, CHRNB2-CHRNB4 and NRXN1 genes and 37 ancestry-informative markers was used to analyze 707 samples (187 HS, 328 LS and 192 NS). In the second stage, 14 SNPs from stage 1 were validated in the remaining samples (HS, LS and NS; n = 414 in each group) using real-time PCR. To predict the role of the associated SNPs, an in silico analysis was performed. RESULTS: Two SNPs in NRXN1 and two in CHRNA5 were associated with cigarette consumption, while rs10865246/C (NRXN1) was associated with high nicotine addiction. The in silico analysis revealed that rs1882296/T had a high level of homology with Hsa-miR-6740-5p, which encodes a putative miRNA that targets glutamate receptor subunits (GRIA2, GRID2) and GABA receptor subunits (GABRG1, GABRA4, GABRB2), while rs1882296/C had a high level of homology with Hsa-miR-6866-5p, which encodes a different miRNA that targets GRID2 and GABRB2. CONCLUSION: In a Mexican Mestizo population, greater consumption of cigarettes was influenced by polymorphisms in the NRXN1 and CHRNA5 genes. We proposed new hypotheses regarding the putative roles of miRNAs that influence the GABAergic and glutamatergic pathways in smoking addiction.
Assuntos
Moléculas de Adesão Celular Neuronais/genética , Proteínas do Tecido Nervoso/genética , Polimorfismo de Nucleotídeo Único/genética , Receptores de GABA/fisiologia , Receptores de Glutamato/fisiologia , Receptores Nicotínicos/genética , Fumar/genética , Adulto , Idoso , Proteínas de Ligação ao Cálcio , Estudos Transversais , Feminino , Estudos de Associação Genética/métodos , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Moléculas de Adesão de Célula Nervosa , Análise de Componente Principal/métodos , Fumar/epidemiologia , Fumar/terapia , Abandono do Hábito de Fumar/métodosRESUMO
The N-acylhydrazone (NAH) analogues N-methyl 2-thienylidene 3,4-benzoylhydrazine (LASSBio-785) and N-benzyl 2-thienylidene 3,4-benzoylhydrazine (LASSBio-786) were prepared from 2-thienylidene 3,4-methylenedioxybenzoylhydrazine (LASSBio-294). The ability of LASSBio-785 and LASSBio-786 to decrease central nervous system activity was investigated in male Swiss mice. LASSBio-785 or LASSBio-786 (30â mg/kg, ip) reduced locomotor activity from 209 ± 26 (control) to 140 ± 18 (P < 0.05) or 146 ± 15 crossings/min (P < 0.05), respectively. LASSBio-785 (15 or 30â mg/kg, iv) also reduced locomotor activity from 200 ± 15 to 116 ± 29 (P < 0.05) or 60 ± 16 crossings/min (P < 0.01), respectively. Likewise, LASSBio-786 (15 or 30â mg/kg, iv) reduced locomotor activity from 200 ± 15 to 127 ± 10 (P < 0.01) or 96 ± 14 crossings/min (P < 0.01), respectively. Pretreatment with flumazenil (20â mg/kg, ip) prevented the locomotor impairment induced by NAH analogues (15â mg/kg, iv), providing evidence that the benzodiazepine (BDZ) receptor is involved. This finding was supported by the structural similarity of NAH analogues to midazolam. However, LASSBio-785 showed weak binding to the BDZ receptor. LASSBio-785 or LASSBio-786 (30â mg/kg, ip, n = 10) increased pentobarbital-induced sleeping time from 42 ± 5 (DMSO) to 66 ± 6 (P < 0.05) or 75 ± 4â min (P < 0.05), respectively. The dose required to achieve 50% hypnosis (HD50) following iv injection of LASSBio-785 or LASSBio-786 was 15.8 or 9.5â mg/kg, respectively. These data suggest that both NAH analogues might be useful for the development of new neuroactive drugs for the treatment of insomnia or for use in conjunction with general anesthesia.
Assuntos
Hidrazinas/farmacologia , Hidrazonas/farmacologia , Hipnóticos e Sedativos/farmacologia , Atividade Motora/efeitos dos fármacos , Receptores de GABA/efeitos dos fármacos , Tiofenos/farmacologia , Animais , Hidrazinas/química , Hidrazonas/química , Masculino , Camundongos , Receptores de GABA/fisiologia , Tiofenos/químicaRESUMO
The N-acylhydrazone (NAH) analogues N-methyl 2-thienylidene 3,4-benzoylhydrazine (LASSBio-785) and N-benzyl 2-thienylidene 3,4-benzoylhydrazine (LASSBio-786) were prepared from 2-thienylidene 3,4-methylenedioxybenzoylhydrazine (LASSBio-294). The ability of LASSBio-785 and LASSBio-786 to decrease central nervous system activity was investigated in male Swiss mice. LASSBio-785 or LASSBio-786 (30 mg/kg, ip) reduced locomotor activity from 209 ± 26 (control) to 140 ± 18 (P < 0.05) or 146 ± 15 crossings/min (P < 0.05), respectively. LASSBio-785 (15 or 30 mg/kg, iv) also reduced locomotor activity from 200 ± 15 to 116 ± 29 (P < 0.05) or 60 ± 16 crossings/min (P < 0.01), respectively. Likewise, LASSBio-786 (15 or 30 mg/kg, iv) reduced locomotor activity from 200 ± 15 to 127 ± 10 (P < 0.01) or 96 ± 14 crossings/min (P < 0.01), respectively. Pretreatment with flumazenil (20 mg/kg, ip) prevented the locomotor impairment induced by NAH analogues (15 mg/kg, iv), providing evidence that the benzodiazepine (BDZ) receptor is involved. This finding was supported by the structural similarity of NAH analogues to midazolam. However, LASSBio-785 showed weak binding to the BDZ receptor. LASSBio-785 or LASSBio-786 (30 mg/kg, ip, n = 10) increased pentobarbital-induced sleeping time from 42 ± 5 (DMSO) to 66 ± 6 (P < 0.05) or 75 ± 4 min (P < 0.05), respectively. The dose required to achieve 50% hypnosis (HD50) following iv injection of LASSBio-785 or LASSBio-786 was 15.8 or 9.5 mg/kg, respectively. These data suggest that both NAH analogues might be useful for the development of new neuroactive drugs for the treatment of insomnia or for use in conjunction with general anesthesia.
Assuntos
Animais , Masculino , Camundongos , Hidrazinas/farmacologia , Hidrazonas/farmacologia , Hipnóticos e Sedativos/farmacologia , Atividade Motora/efeitos dos fármacos , Receptores de GABA/efeitos dos fármacos , Tiofenos/farmacologia , Hidrazinas/química , Hidrazonas/química , Receptores de GABA/fisiologia , Tiofenos/químicaRESUMO
BACKGROUND AND PURPOSE: NO is a highly diffusible and reactive gas produced in the nervous system, which acts as a neuronal signal mediating physiological or pathological mechanisms. NO can modulate the activity of neurotransmitter receptors and ion channels, including NMDA and GABA(A) receptors. In the present work, we examined whether GABA(C) receptor function can also be regulated by NO. EXPERIMENTAL APPROACH: Homomeric ρ1 GABA(C) receptors were expressed in oocytes and GABA-evoked responses electrophysiologically recorded in the presence or absence of the NO donor DEA. Chemical protection of cysteines by selective sulfhydryl reagents and site-directed mutagenesis were used to determine the protein residues involved in the actions of NO. KEY RESULTS: GABAρ1 receptor responses were significantly enhanced in a dose-dependent, fast and reversible manner by DEA and the specific NO scavenger CPTIO prevented these potentiating effects. The ρ1 subunits contain only three cysteine residues, two extracellular at the Cys-loop (C177 and C191) and one intracellular (C364). Mutations of C177 and C191 render the ρ1 GABA receptors non-functional, but C364 can be safely exchanged by alanine (C364A). NEM, N-ethyl maleimide and (2-aminoethyl) methanethiosulfonate prevented the effects of DEA on GABAρ1 receptors. Meanwhile, the potentiating effects of DEA on mutant GABAρ1(C364A) receptors were similar to those observed on wild-type receptors. CONCLUSIONS AND IMPLICATIONS: Our results suggest that the function of GABA(C) receptors can be enhanced by NO acting at the extracellular Cys-loop.
Assuntos
Óxido Nítrico/fisiologia , Receptores de GABA/fisiologia , Animais , Benzoatos/farmacologia , Metanossulfonato de Etila/análogos & derivados , Metanossulfonato de Etila/farmacologia , Etilmaleimida/farmacologia , Hidrazinas/farmacologia , Imidazóis/farmacologia , Doadores de Óxido Nítrico/farmacologia , Oócitos , S-Nitrosoglutationa/farmacologia , Xenopus laevis , Ácido gama-Aminobutírico/farmacologiaRESUMO
The electrophysiological characterization of sesquiterpene lactones from Coriaria ruscifolia subsp. ruscifolia has been tested on hippocampal neurons. The results for glycinergic rat hippocampal transmission and native γ-aminobutyric acid (GABA)ergic transmission on neurons (13DIV) are remarkably different for tutin, coriamyrtin, and dihydrotutin, being tutin the most potent inhibitor and dihydrotutin the least potent one. To understand the applied mechanism of action, we discuss the structural and electronic requirements for inhibitory activity by these sesquiterpene lactones when modulating receptors of the central nervous system. The structural and electrostatic properties of these compounds were compared to those of more active metabolites like picrotoxins. The minimal energy level of these structures was calculated and then optimized at the ab initio B3LYP/DGDZVP level of theory using Gaussian 03W software. This allowed calculation of the corresponding vibrational circular dichroism spectrum of coriamyrtin which rendered the molecular absolute configuration after comparison with an experimental spectrum. These results are consistent with those from studies of other models that provide the basis for the activity on the presence of the lactone at carbons 3 and 5, the presence of the hydroxyl group at position 6, and the different electronic distributions observed in tutin and coriamyrtin. The latter has an isopropenyl moiety at carbon 4 in contrast to the dihydrotutin isopropyl group at the same position, which could explain the difference in activity between dihydrotutin and tutin or coriamyrtin. The presence of the hydroxyl group at carbon 2 is not decisive since this functionality is present in tutin, the most active compound, and in dihydrotutin, the less active one.
Assuntos
Biologia Computacional , Inibição Neural/efeitos dos fármacos , Picrotoxina/análogos & derivados , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Sesquiterpenos/farmacologia , Animais , Células Cultivadas , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/fisiologia , Biologia Computacional/métodos , Lactonas/química , Lactonas/isolamento & purificação , Lactonas/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Inibição Neural/fisiologia , Neurônios/química , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Picrotoxina/química , Picrotoxina/isolamento & purificação , Picrotoxina/farmacologia , Receptores Citoplasmáticos e Nucleares/fisiologia , Receptores de GABA/fisiologia , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Difração de Raios XRESUMO
γ-amino butyric acid (GABA) is an ubiquitous neurotransmitter in the central nervous system and it is also present in non-neuronal cells. In this study we investigated the presence of neuronal components of the GABAergic system in lymphocytes and its functional significance. By using RT-PCR we detected mRNA expression of different components of the GABAergic system in resting and mitogen-activated lymphocytes: i) GAD67, an isoform of the enzyme that synthetizes GABA; ii) VIAAT, the vesicular protein involved in GABA storage; iii) GABA transporters (GAT-1 and GAT-2); iv) GABA-T, the enzyme that catabolizes GABA; and v) subunits that conform ionotropic GABA receptors. The presence of VIAAT protein in resting and activated cells was confirmed by immunocytochemistry. The functionality of GABA transporters was evaluated by measuring the uptake of radioactive GABA. The results show that [(3)H]GABA uptake is 5-fold higher in activated than in resting lymphocytes. To determine if GABA subunits assemble into functional channels, we performed whole-cell recordings in activated lymphocytes. GABA and muscimol, a specific agonist of ionotropic GABA receptors, elicit macroscopic currents in about 10-15% of the cells. Finally, by using [(3)H]thymidine incorporation assays, we determined that the presence of agonists of GABA receptor during activation inhibits lymphocyte proliferation. Our results reveal that lymphocytes have a functional GABAergic system, similar to the neuronal one, which may operate as a modulator of T-cell activation. Pharmacological modulation of this system may provide new approaches for regulation of T-cell response.
Assuntos
Proteínas da Membrana Plasmática de Transporte de GABA/fisiologia , Linfócitos/metabolismo , Receptores de GABA/fisiologia , Ácido gama-Aminobutírico/fisiologia , Adulto , Células Cultivadas , Feminino , Glutamato Descarboxilase/fisiologia , Humanos , Masculino , Proteínas Vesiculares de Transporte de Aminoácidos Inibidores/fisiologia , Adulto JovemRESUMO
Most of the gamma-aminobutyric acid (GABA)ergic interneurons in the cerebral cortex originate from restricted regions of the ventral telencephalon known as the caudal and medial ganglionic eminence (MGE) and from the preoptic area. It is well established that dysfunction of GABAergic interneurons can lead to epilepsy. During the last decade new approaches to prevent, reduce, or reverse the epileptic condition have been studied, including cell-based therapy from different sources. Recent studies have shown that transplanted neuronal precursor cells derived from MGE have the ability to migrate, differentiate into inhibitory GABAergic interneurons, and integrate into cortical and hippocampal networks, modifying the inhibitory tone in the host brain. Therefore, transplantation of neuronal precursors derived from MGE into the postnatal central nervous system (CNS) could modify the neuronal circuitry in neurologic diseases in which inhibitory synaptic function is altered, such as in epilepsy. Here, we evaluated the seizure susceptibility of mice transplanted with MGE-derived cells in the maximum electroconvulsive shock (MES) model and we review some data from different studies using GABAergic precursor or GABA-releasing cell grafts in animal models of seizure and epilepsy.
Assuntos
Células-Tronco Embrionárias/transplante , Epilepsia/cirurgia , Telencéfalo/citologia , Animais , Córtex Cerebral/fisiopatologia , Modelos Animais de Doenças , Epilepsia/etiologia , Epilepsia/fisiopatologia , Hipocampo/fisiopatologia , Interneurônios/fisiologia , Camundongos , Ratos , Receptores de GABA/fisiologia , Sinapses/fisiologia , Telencéfalo/transplanteRESUMO
Hasta el momento, los estudios realizados sobre la participación de los receptores GABAB (REGABAB) en la regulación neuroendocrina habían sido llevados a cabo a través de abordajes farmacológicos, mediante la utilización de agonistas y antagonistas específicos. En el presente trabajo utilizamos el modelo de ratón GABA para analizar las consecuencias endocrinas de la falta constitutiva de los RGABAB en la unidad hipotálamo-hipófiso-gonadal. No observamos diferencias en los contenidos hipofisarios ni en los niveles séricos de LH y FSH entre los genotipos en ningún sexo. Sin embargo, nuestros estudios in vitro, demostraron la existencia de alteraciones de la fisiología de los gonadotropos provenientes de hembras GABA, con una secreción basal aumentada de gonadotropinas y una menor respuesta el estímulo con GnRH. Al analizar más específicamente la funcionalidad del eje en esos ratones, encontramos alteraciones en el aumento de LH postcastración en las hembras, confirmando la participación de los RGABAB en este fenómeno. Por otro lado, en la hemras GABA adultas demostramos la presencia de alteraciones en el contenido hipotalámico de GnRH, el cual estaba francamente disminuido, y su secreción pulsátil, en la que se observa un aumento significativo de la frecuencia de los pulsos de GnRH. También observamos un aumento en los contenidos hipotalámicos de neurotransmisores aminoacídicos que podrían afectar la liberación de GnRH...