5-HT2A receptor

The mammalian 5-HT_2A receptor is a subtype of the 5-HT₂ receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor (GPCR). This is the main excitatory receptor subtype among the GPCRs for serotonin (5-HT), although 5-HT_2A may also have an inhibitory effect on certain areas such as the visual cortex and the orbitofrontal cortex. This receptor was first given importance as a target of serotonergic psychedelic drugs such as LSD. Later it came back to prominence because it was also found to be mediating, at least partly, the action of many antipsychotic drugs, especially the atypical ones.

5-HT_2A may be a necessary receptor for the spread of the human polyoma virus called JC virus.

Downregulation of post-synaptic 5-HT_2A receptor is an adaptive process provoked by chronic administration of selective serotonin reuptake inhibitors (SSRIs) and classical antipsychotics. Deceased suicidal and otherwise depressed patients have had more 5-HT_2A receptors than normal patients. These findings suggest that post-synaptic 5-HT_2A overdensity is involved in the pathogenesis of depression.