The mammalian 5-HT2A 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-HT2A 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.