Melatonin is

(A) Serotonergic # Melatonin is synthesized by pineal parenchymal cells and secreted by them into the blood and CSF.> It is synthesized from serotonin by N-acetylation and O-methylation.> Formation and metabolism of Melatonin: Tryptophan; 5-Hydroxytryptophan 5-Hydroxytryptamine (Serotonin) N-Acetyl -5-methoxytryptamine < (Melatonin) N-Acetyl-Serotonin metabolism 6-Hydroxymelatonin (in Liver) & other metabolites (in brain)