Melatonin synthesis and secretion by the pineal gland is under the control of the suprachiasmatic nucleus and consequently has a profound circadian rhythm. In this review we discuss some of the issues surrounding the measurement of melatonin rhythmicity in biological fluids and the factors that influence melatonin circadian rhythmicity, including light and drugs. We also review the role of melatonin rhythmicity in sleep timing and sleep initiation.
Keywords: Circadian Rhythms, melatonin rhythmicity, N-methyl-D-aspartate