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 GABAA receptor. GABA_B receptors, which are G protein-coupled receptors, are less plentiful in the brain than GABA_A receptors and do not have binding sites for benzodiazepine or barbiturate GABA agonists. Activation of GABA_B receptors results in relatively long-lasting neuronal inhibition, but few psychotropic substances exert their effect at these receptors: Baclofen is a relatively selective agonist at GABA_B receptors and is used clinically as a skeletal muscle relaxant.