Melatonin Receptor 1 (MT1)

Melatonin Receptor 1 (MT1), also known as Melatonin receptor 1A (gene symbol: MTNR1A), is one of two high-affinity G protein-coupled receptors (GPCRs) for melatonin, the primary hormone secreted by the pineal gland. It plays a key role in regulating sleep, particularly REM sleep, and entraining circadian rhythms. MT1 receptors are expressed in several brain regions and peripheral tissues, including the suprachiasmatic nucleus (SCN), pars tuberalis of the pituitary gland, and retina. Activation of MT1 primarily couples to Gi proteins, leading to inhibition of adenylyl cyclase activity and reduced intracellular cAMP levels. Altered expression or function is linked with mood disorders, and knockout mice display increased anxiety-like behavior. Selective ligands targeting only one subtype may offer improved therapeutic outcomes.

Other names

Melatonin receptor 1AMTNR1A

Agonist binding to MT1 leads to Gi protein activation, inhibiting adenylyl cyclase and reducing cAMP levels. Can also couple to Gq/11 proteins and affect MAPK/ERK pathways.