5-HT receptor

In the field of neurochemistry, 5-HT receptors are receptors for the neurotransmitter and peripheral signal mediator serotonin, also known as 5-hydroxytryptamine or 5-HT. 5-HT receptors are located on the cell membrane of nerve cells and other cell types in animals and mediate the effects of serotonin as the endogenous ligand and of a broad range of pharmaceutical and hallucinogenic drugs. With the exception of the 5-HT3 receptor, a ligand gated ion channel, all other 5-HT receptors are G protein coupled seven transmembrane (or heptahelical) receptors that activate an intracellular second messenger cascade.


 * 5-HT1 receptors are Gi/Go coupled, mediating cellular effects through decreasing cellular levels of cyclic adenosine monophosphate (cAMP).


 * 5-HT2 receptors are Gq/G11 coupled, mediating cellular effects through increasing cellular levels of inositol trisphosphate (IP3) and diacylglycerol (DAG). Three subtypes exist, namely 5-HT2A, 5-HT2B, and 5-HT2C (formerly called 5-HT1C).


 * The 5-HT3 receptor is a ligand-gated Na+ and K+ cation channel, resulting in a direct plasma membrane depolarization.


 * The 5-HT4 receptor is Gs coupled, mediating cellular effects through increasing cellular levels of cAMP.


 * The 5-HT7 receptor is Gs coupled, mediating cellular effects through increasing cellular levels of cAMP.

Characterized 5-HT receptors
Within these general classes of 5-HT receptors, a number of specific types have been characterized:

Note that there is no 5-HT1C receptor since, after the receptor was cloned and further characterized, it was found to have more in common with the 5-HT2 family of receptors and was redesignated as the 5-HT2C receptor.

Therapeutic modulation
Various drugs are used to modulate the 5-HT system including some antidepressants, anxiolytics, and antiemetics.