Gamma-aminobutyric acid receptor (GABA receptor)

The Gamma-aminobutyric acid (GABA) receptor is the primary receptor for GABA, the chief inhibitory neurotransmitter in the mature vertebrate central nervous system. It comprises two main classes: GABAA and GABAB. GABAA receptors are ligand-gated ion channels forming pentameric structures from 19 potential subunits (alpha, beta, gamma, rho, delta, epsilon, pi, theta). The most common GABAA composition is α2β2γ1. These receptors mediate fast synaptic, tonic, and slow inhibition by opening chloride channels, leading to neuronal hyperpolarization. A subclass, GABAA-ρ (formerly GABAC), are composed exclusively of rho subunits and are found primarily in the retina, insensitive to typical GABAA allosteric modulators. GABAA receptors have multiple binding sites for GABA, benzodiazepines, barbiturates, steroids, and other compounds. GABAB receptors are G protein-coupled receptors that mediate slow inhibitory responses to GABA. They are pharmacologically distinct from GABAA receptors, being insensitive to bicuculline and isoguvacine but activated by baclofen. Various drugs, including benzodiazepines, barbiturates, muscimol, gaboxadol, baclofen, bicuculline, and isoguvacine, interact with GABA receptors at distinct binding sites, modulating their activity and influencing neuronal inhibition.

Other names

GABAA receptorGABAB receptorGABAC receptor

GABA receptors are a class of receptors that respond to the inhibitory neurotransmitter GABA. GABAA receptors are ligand-gated ion channels (specifically chloride channels) that, upon GABA binding, open to allow chloride influx, hyperpolarizing the neuron and inhibiting activity. Allosteric modulators like benzodiazepines increase the frequency of channel opening, while barbiturates increase the duration. Agonists like muscimol and gaboxadol bind to the GABA site. GABAB receptors are G protein-coupled receptors that mediate slower inhibitory responses, activated by compounds like baclofen and not dependent on chloride flux.