Serotonin receptor physiology - Relation to emesis

Several serotonin (5-HT) receptor subtypes have been defined by pharmacolog ical responses to selective agonists and antagonists and by pathways of rec eptor-effector coupling. Using molecular techniques, additional receptor su btypes have been described. 5-HT receptors are prevalent in the central ner vous system and gut and participate in induction of emesis. 5-HT3 antagonis ts are used to prevent emesis from cancer chemotherapy and also demonstrate efficacy in radiation-induced nausea, postoperative nausea, hyperemesis gr avidarum, and nausea and vomiting with the acquired immunodeficiency syndro me. 5-HT4 agonists exhibit prokinetic properties in nauseated patients with gastroparesis and functional dyspepsia. Conversely, 5-HT4 antagonists have antiemetic activity in some experimental models. The 5-HT1D receptor agoni st sumatriptan reduces emesis with migraine headaches and in cyclic vomitin g syndrome, most likely via action on central nervous system sites. In othe r models, 5-HT1A and 5-HT2A/5-HT2C agonists exhibit antiemetic properties. The utility of 5-HT receptor ligands in treating emesis is the subject of a ctive investigation.