serotonin receptor
any of various receptors that bind and respond to serotonin (5-hydroxytryptamine; 5-HT). They occur in the brain and in peripheral areas and have different sensitivities that can be measured by susceptibility to ligands or blockers. At least 15 classes of serotonin receptors, affecting a variety of physiological and psychological processes, have been identified. They are designated by subscript numbers and letters (e.g., 5-HT1A, 5-HT1B, 5-HT1D, 5-HT2A).