Abstract
Melatonin (5-methoxy-acetyl tryptamine) is a sleep-inducing hormone, and the
pineal gland produces it in response to the circadian clock of darkness. In the
body, MT1 and MT2 receptors are mostly found, having an orthosteric pocket and
ligand binding determinants. Melatonin acts by binding on melatonin receptors,
intracellular proteins, and orphan nuclear receptors. It inhibits adenyl cyclase
and activates phospholipase C, resulting in gene expression and an intracellular
alteration environment. Melatonin signaling pathways are also associated with
other intracellular signaling pathways, i. e., cAMP/PKA and
MAPK/ERK pathways. Relative expression of different proteins depends on
the coupling profile of G protein, accounting pharmacology of the melatonin
receptor bias system, and mediates action in a Gi-dependent manner. It shows
antioxidant, antitumor, antiproliferative, and neuroprotective activity.
Different types of melatonin agonists have been synthesized for the treatment of
sleeping disorders. Researchers have developed therapeutics that target
melatonin signaling, which could benefit a wide range of medical conditions.
This review focuses on melatonin receptors, pharmacology, and signaling
cascades; it aims to provide basic mechanical aspects of the receptor’s
pharmacology, melatonin’s functions in cancer and neurodegenerative
diseases, and any treatments and drugs designed for these diseases. This will
allow a basic comparison between the receptors in question, highlighting any
parallels and differences that may exist and providing fundamental knowledge
about these receptors to future researchers.
Keywords
melatonin - receptor structure - receptor signaling cascade - pineal gland
