APA Dictionary of Psychology

a compound that exerts an agonistic (augmentative) effect at gamma-aminobutyric acid (GABA) receptor sites (see GABAA receptor; GABAB receptor) or on the action of GABA. Several classes of GABA agonists exist. Direct GABA agonists (e.g., muscimol) act at the GABA binding site on the receptor; indirect GABA agonists facilitate, in various ways, the release or activity of GABA. Of the indirect GABA agonists, the benzodiazepines, which act as allosteric modulators (see allosteric modulation) at the GABA receptor complex, are in the most common clinical use.