serotonin receptor subtype 5, member of the class A family of seven-transmembrane G protein-coupled receptors
5-HT5 receptor, one of 14 mammalian 5-HT receptors, is activated by the neurotransmitter and peripheral signal mediator serotonin (also known as 5-hydroxytryptamine or 5-HT). The 5-HT5A and 5-HT5B receptors have been cloned from rat and mouse, but only the 5-HT5A isoform has been identified in human because of the presence of premature stop codons in the human 5-HT5B gene, which prevents a functional receptor from being expressed. 5-HT5 receptors mediate inhibitory neurotransmission by coupling to G proteins of the G(i/0) family, which lead to a decrease in adenylate cyclase activity, thereby decreasing intracellular cAMP levels and calcium influx. In the CNS, serotonin is involved in the regulation of appetite, mood, sleep, cognition, learning and memory, as well as implicated in neurologic disorders such as migraine, schizophrenia, and depression.