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Melatonin and Stroke Recovery

Aug 18, 2011 | By Don Amerman

Melatonin is a naturally occurring hormone that is secreted by the pineal gland in the brain. It plays a central role in the maintenance of the body's internal clock, known as circadian rhythm, which determines when you wake up and fall asleep. In supplement form, the hormone is often used in the treatment of sleep disorders. Research has uncovered evidence that melatonin's neuroprotective properties can speed recovery from strokes. Consult your doctor before using melatonin.

Significance of Stroke Timing

Because of its role in maintaining circadian rhythm, melatonin levels in the brain are higher during nighttime hours than during the day. Based on animal studies, two researchers at the Psychiatric Institute of the University of Illinois, Chicago, hypothesized that stroke damage is greater during the daylight hours precisely because melatonin levels are at the lowest ebb during the day. They published their findings in the May-June 1998 issue of the "Journal of Stroke and Cerebrovascular Diseases."

Anti-Inflammatory Activity in CNS

Two Italian researchers at the University of Messina undertook a study of the scientific literature to review what research has uncovered about melatonin's anti-inflammatory activity in the central nervous system, or CNS. In an article in the September 2010 issue of "Current Pharmacology," they pointed out that although the pineal gland secretes most of the body's melatonin, other body tissues produce the hormone as well. Such tissues include the retina, gut, ovary, testes and bone marrow. They also reported that multiple studies have confirmed the ability of melatonin to reduce both acute and chronic inflammation. Based on their review of hundreds of studies on melatonin's activity in the CNS, the researchers conclude that ample evidence exists to provide the foundation for designing and carrying out clinical trials using the hormone as a neuroprotective agent for traumatic CNS injuries, including stroke.

Antioxidative Properties

Researchers at California's Loma Linda University Medical Center conducted a study to assess melatonin's antioxidant effects on the rate of recovery of laboratory rats in which researchers had induced intracerebral hemorrhage, a form of stroke. Aware that free radicals play a central role in the mechanism of brain injury following a hemorrhagic stroke, researchers wanted to learn to what degree melatonin could protect the brain from free radical damage. Researchers treated rats with low doses of melatonin -- 5 mg per kg of body weight -- one hour after induction stroke and once every 24 hours for the next three days. Rats treated with melatonin showed less brain atrophy two weeks after stroke and exhibited normal striatal function and memory ability over the course of eight weeks. In an article in the March 2010 issue of the "Journal of Neurotrauma," the study team said its findings strongly suggest that melatonin is safe for use after hemorrhagic stroke and that it reduces oxidative stress and protects the brain.

Delayed Treatment Also Effective

Taiwanese researchers found that treatment with melatonin well after the occurrence of a stroke still significantly improves outcome. Researchers induced transient cerebral ischemia in laboratory rats, which were treated intravenously with melatonin 72 hours after a stroke. Reporting their findings in the January 2004 issue of the "Journal of Pineal Research," researchers said delayed melatonin administration "enhances electrophysiological and neurobehavioral recoveries and reduces cortical and striatal infarct sizes after cerebral ischemia and reperfusion injury."

References

Article reviewed by Avraham Zuroff Last updated on: Aug 18, 2011

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