Melatonin Is Produced by the Pineal Gland and Is Stimulated by Darkness and Inhibited by Light

Melatonin

·  Researches carry out studies of the hormone melatonin in the hope to find a solution for those who suffer from insomnia and jet lag.

·  Melatonin is produced by the pineal gland and is stimulated by darkness and inhibited by light

o  reddish-gray and about the size of a pea.

o  It is shaped like a tiny pinecone, near center of the brain,

o  between the two hemispheres,

o  tucked in a groove where the two rounded thalamic bodies join

·  The body produces melatonin when there is a complete absence of light when you sleep

·  Melatonin levels in the bloodstream peak in the middle of the night and gradually decrease towards morning

·  During winter, as the days get shorter, the earlier appearance of darkness can make us tired earlier

o  Melatonin release correlates with the biological clock that is based on a 24-hour day/night cycle, which is known as the circadian rhythm

o  Taking melatonin early in the evening may improve one’s ability to fall asleep

Rosenthal (1987)

Bemonstrated that higher levels of melatonin contribute to SAD, which stands for seasonal affective disorder. It is a subcategory of depression due to sleepiness and lethargy, and cravings for carbohydrates. Higher levels of SAD are seen in Scandinavia as there is a reduced level of sunlight in cold weathers.Increased sunlight improves the symptoms.Phototherapy is the main treatment for people with SAD. Exposal to bright light for several hours each day

Carskadon et al.
Aimedto look at the changes in melatonin secretion at different adolescents of different physical maturity. Carskadon developed a experimental protocol to control behaviors, such as a later bedtime and hence later exposure of light which was known to affect the circadian timing system. Participants were kept on the same schedule for a couple of days at home and in the laboratory. Sample of their saliva were collected at specfic and various times during the day and night. Study found that melatonin production turned off later in more mature adolescents, indicating that the brain’s nighttime cycle has shifted to a later phase.