Serotonin is biosynthesised from the amino acid, tryptophan. It is the precursor compound to the sleep-modulating hormone, melatonin. It binds to, activates and serves as the endogenous ligand for the 5-HT family of receptors which includes:
The 5-HT1 family:
The 5-HT2 family:
It plays a key role in mood regulation, sleep, anxiety, cognition and sensory perception.
Figure 1: Serotonin [Source: Chemspider]