Gamma-aminobutyric acid receptor (GABA receptor) (GABA receptor)

Gamma‐aminobutyric acid‐mediated inhibitory neurotransmission refers to the process by which gamma‐aminobutyric acid (**GABA**), the principal inhibitory neurotransmitter in the mammalian central nervous system, reduces neuronal excitability. This is achieved through its action on two main classes of receptors: **GABA-A receptors** are ligand-gated chloride channels that mediate fast synaptic inhibition. When activated by binding to extracellularly released GABA from presynaptic neurons, they allow an influx of chloride ions into postsynaptic cells. This hyperpolarizes neurons and decreases their likelihood to fire action potentials.[1][2][4] **GABA-B receptors** are metabotropic/G protein-coupled receptors that mediate slower forms of inhibition via second messenger systems. Activation leads to opening potassium channels and closing calcium channels through intracellular signaling cascades—further reducing neuronal excitability.[1] These processes maintain a critical balance between excitation and inhibition within neural circuits; disruption can lead to neurological diseases including epilepsy, anxiety disorders, sleep disturbances, hepatic encephalopathy, psychiatric illnesses such as schizophrenia/depression,[6] among others. A wide range of clinically important drugs—including benzodiazepines, barbiturates, certain anticonvulsants/antiepileptics—target components involved in this pathway for therapeutic effect but also carry risks related to excessive CNS suppression.[3][7]

Other names

GABAergic receptorsGABAA receptorGABAB receptorGamma-aminobutyric acid-gated chloride channel (for GABAA)Metabotropic GABA receptor (for GABAB)

Drugs targeting these molecules act by one or more of the following mechanisms: - Positive allosteric modulation of chloride influx via ligand-gated ion channels to enhance inhibition at postsynaptic neurons (benzodiazepines/barbiturates on GABAA)[5][8] - Direct agonism or antagonism at orthosteric binding sites on either ionotropic or metabotropic receptors - Inhibition of reuptake or breakdown to increase synaptic levels of endogenous ligand