APA Dictionary of Psychology

one of the two main types of receptor protein that bind the neurotransmitter gamma-aminobutyric acid (GABA), the other being the GABAB receptor. It is located at most synapses of most neurons that use GABA as a neurotransmitter. The predominant inhibitory receptor in the central nervous system, it functions as a chloride channel (see ion channel). GABA agonists, such as the barbiturates and benzodiazepines, enhance the binding of GABA to GABA_A receptors, allowing for increased conductance of chloride through the ion channel and thereby hyperpolarizing the neuron and inhibiting its activity. GABA antagonists, such as bicuculline and picrotoxin, block the inhibitory effects of GABA at this receptor. Many other substances, including alcohol (ethanol), are thought to exert at least part of their effect via interaction at the GABA_A receptor.