signaling pathway pertinent to the brain and nervous system amine and amino acid-derived hormone signaling pathway chemical compound signaling pathway melatonin signaling pathway 2016-02-05T12:33:57Z Melatonin, in human and other organisms derived from tryptophan, is a monoamine with antioxidant properties and involved in the synchronization of the circadian rhythms. Melatonin signals through three receptors types of which two are present in humans and other mammals. They are G protein coupled receptors (GPCR). PW:0002489 pathway vpetri