Literatus: Beyond the sleep cycle

Zosimo T. Literatus

MELATONIN is renowned in the biomedical sciences as a neurohormone that plays an important role in regulating our sleep-wake or night-day cycle. It is naturally produced within our body, particularly by the pineal gland. It’s the pine cone-like gland located near the center of the brain (epithalamus).

Melatonin is the reason why you get sleepy at night and automatically wake up in the morning. It is so because darkness increases the production of melatonin. A high concentration of melatonin in the blood prepares the body to sleep, causing drowsiness. This explains why working in a darkened room makes you sleepy.

Conversely, light has an opposite effect. It decreases the production of melatonin. A low concentration of melatonin in the blood prepares the body to wake up. This explains why you easily wake up in the morning when your window is open through which the sunlight can get through.

People who have insomnia have unnaturally low production level of melatonin so that even at night the pineal gland cannot secrete more melatonin as it normally does.

However, that is not the only function of melatonin in the body. Melatonin also influences the human mental state. Normal levels of melatonin prevent depression and anxiety. It also prevents nerve-associated pain, among others.

This hormone is also associated with autoimmune disorders. Charalampos Skarlis and Maria Anagnostouli of the Immunogenetics Laboratory of the Kapodistrian University of Athens reported in last month’s issue of the Neurological Sciences, that impairment in the regulation of its secretion had been associated with the development of rheumatoid arthritis (RA), multiple sclerosis (MS) and systematic lupus erythematosus (SLE).

In RA, the human immune system automatically attacks the “synovium,” the thin membrane lining the joints. This causes warmth, pain, stiffness, swelling and eventually, inflammation of all joints in the body. Uncured, the joints can be permanently damaged and deformed.

In MS, the immune system automatically attacks the myelin sheath in the central nervous system (i.e. in the brain and in the spinal cord). This results to the disappearance of these nerve-protective sheaths, deaths of the insulating nerve cells and degeneration of the nerve fibers.

In SLE, the immune system automatically attacks healthy tissues in the body. These tissues include the brain, joints, kidneys, lungs, skin and spinal cord. In a sense, symptoms of abnormal melatonin secretion may increase the risk of these autoimmune diseases.

Do not ignore symptoms of impaired melatonin regulation.