Combining with melatonin, N-acetyl-5-methoxytryptamine, to initiate a change in cell activity. Melatonin is a neuroendocrine substance that stimulates the aggregation of melanosomes in melanophores, thus lightening the skin. [ GOC:ai https://www.worldcat.org/search?q=bn%3A0198506732 ]
This is just here as a test because I lose it