5-Hydroxytryptamine (serotonin) receptor 5A, also known as HTR5A, is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...

that in humans is encoded by the ''HTR5A''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. Agonists and antagonists for 5-HT receptors, as well as serotonin uptake inhibitors, present promnesic (memory-promoting) and/or anti-amnesic effects under different conditions, and 5-HT receptors are also associated with neural changes.

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 protein G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their ...

s, 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 a 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.

Selective ligands

Few highly selective ligands are commercially available for the 5-HT_5A receptor. When selective activation of this receptor is desired in scientific research, the non-selective serotonin receptor agonist 5-Carboxamidotryptamine can be used in conjunction with selective antagonists for its other targe