How does the presence of melatonin influence sleep and waking up??

Melatonin is secreted from Pineal Gland which is located on the dorsal side of forebrain. Melatonin plays a very important role in regulation of the 24-hour (diurnal) rhythm of our body.It's level in the body rises in the evening and throughout the night and drops around noon.It have its maximum concentration at midnight and minimum during noon.Light reduces melatonin formation and hence normal rhythm of sleep-wake cycle.It is also known as biological clock.