5-HT5A receptor

5-Hydroxytryptamine (serotonin) receptor 5A, also known as HTR5A, is a protein that in humans is encoded by the HTR5A gene.

Function

The gene described in this record is a member of 5-hydroxytryptamine receptor family and encodes a multi-pass membrane protein that functions as a receptor for 5-hydroxytryptamine and couples to G proteins, negatively influencing cAMP levels via G_i and G_o. This protein has been shown to function in part through the regulation of intracellular Ca²⁺ mobilization. The 5-HT_5A receptor has been shown to be functional in a native expression system.

Rodents have been shown to possess two functional 5-HT₅ receptor subtypes, 5-HT_5A and 5-HT_5B, however while humans possess a gene coding for the 5-HT_5B subtype, its coding sequence is interrupted by stop codons, making the gene non-functional, and so only the 5-HT_5A subtype is expressed in human brain.

It also appears to serve as an presynaptic serotonin autoreceptor.

Clinical significance

The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) has been implicated in a wide range of psychiatric conditions and also has vasoconstrictive and vasodilatory effects.