serotonin receptor agonist serotonin receptor agonist a serotonin receptor agonist is an agonist of one or more serotonin receptors. they activate serotonin receptors in a manner similar to that of serotonin (5-hydroxytryptamine; 5-ht), a neurotransmitter and hormone and the endogenous ligand of the serotonin receptors. the neurotransmitter serotonin (illustration) has various receptors. non-selective agonists serotonergic psychedelics such as tryptamines (e.g., psilocybin, psilocin, dmt, 5-meo-dmt, bufotenin), lysergamides (e.g., lsd, ergine (lsa)), phenethylamines (e.g., mescaline, 2c-b, 25i-nbome), and amphetamines (e.g., mda, dom) are non-selective agonists of serotonin receptors. their hallucinogenic effects are specifically mediated by activation of the 5-ht2a receptor. drugs that increase extracellular serotonin levels such as serotonin reuptake inhibitors (e.g., fluoxetine, venlafaxine), serotonin releasing agents (e.g., fenfluramine, mdma), and monoamine oxidase inhibitors (e.g., phenelzine, moclobemide) are indirect non-selective serotonin receptor agonists. they are used variously as antidepressants, anxiolytics, antiobsessionals, appetite suppressants, and entactogens. 5-ht1 receptor agonists 5-ht1a receptor agonists azapirones such as buspirone, gepirone, and tandospirone are 5-ht1a receptor partial agonists marketed primarily as anxiolytics, but also as antidepressants. the antidepressants vilazodone and vortioxetine are 5-ht1a receptor partial agonists. flibanserin, a drug used for female sexual dysfunction, is a 5-ht1a receptor partial agonist. many atypical antipsychotics, such as aripiprazole, asenapine, clozapine, lurasidone, quetiapine, and ziprasidone, are 5-ht1a receptor partial agonists, and this action is thought to contribute to their beneficial effects on negative symptoms in schizophrenia. 5-ht1b receptor agonists