Functional characteristics and sites of gene expression of the alpha 1, beta 1, gamma 2-isoform of the rat GABAA receptor.

摘要: GABAA receptors, the major synaptic targets for neurotransmitter GABA, constitute gated chloride channels. By their allosteric, drug- induced modulation, they serve as control elements regulation of anxiety, vigilance, and epileptiform activity. The structural requirements fully functional receptors in mammalian brain have remained elusive so far. We report here on cloning gamma 2-subunit cDNA rat its analysis by coexpression with alpha 1- beta 1-subunits Xenopus oocytes, sites gene expression 3 subunits brain. recombinant receptor displayed GABA-inducible currents (Imax = 6 microA; Ka 75 microM) which were allosterically modulated benzodiazepine ligands (enhancement inhibition diazepam methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate, respectively). In absence pentobarbital elicited a maximal current amplitude similar to that GABA. A minor population channels is expressed open GABA or pentobarbital. Mapping subunit situ hybridization histochemistry suggests 1-, 2- are likely constituents some neuronal populations, e.g., mitral cells olfactory bulb, pyramidal hippocampus, granule dentate gyrus cerebellum.