Three types of melatonin receptor have been cloned.

In mammals, melatonin receptors are found in the brain and some peripheral organs.

However, there is considerable variation in the density and location of the expression of melatonin receptors between species.

They are used for their action on melatonin receptors in the suprachiasmatic nucleus, responsible for sleep-wake cycles.

Additionally, possibly because of its action on melatonin receptors, agomelatine appears to improve sleep quality, with no reported daytime drowsiness.

In 1994 the melatonin receptors were characterized and cloned in the human being.

The binding of melatonin to melatonin receptors activates a few signaling pathways.

The melatonin receptors consist of proteins around 40 kDa each.

The drug, called a melatonin analogue, works by targeting melatonin receptors in the brain.

The drug works by a different mechanism from the others, acting on the brain's melatonin receptors, which are believed to play a role in sleep-wake cycles.