Hormone of Darkness: Melatonin Could Hurt Memory Formation at Night, Researcher Finds
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Dr. Greg Roman
Dr. Greg Roman
Giving
 
By Lisa Merkl
University Communication

What do you do when a naturally occurring hormone in your body turns against you? What do you do when that same hormone – melatonin – is a popular supplement you take to help you sleep? A University of Houston professor and his team of researchers may have some answers.

Gregg W. Roman, assistant professor of biology and biochemistry, describes his team’s findings in a paper entitled “Melatonin Suppresses Nighttime Memory Formation in Zebrafish,” that appeared this past November, the world’s leading journal of original scientific research, global news and commentary.

Frequently called the “hormone of darkness,” melatonin is a hormone the body produces that may regulate patterns of sleeping and awakening in humans. In almost all organisms tested, this antioxidant’s natural levels are high during the night and low during the day. In addition to what the body produces naturally, many people also take melatonin supplements to fight jet lag, balance out seasonal affect disorder and regulate nighttime dementia.

Roman says, however, that melatonin could actually be hurting you at night, finding in a study with zebrafish (Danio rerio) that melatonin directly inhibits memory formation.

“This work is about the mechanism by which the biological clock controls the formation of new memories,” Roman said. “We were interested in the circadian control – the day-night cycle control – of learning and memory formation. We found that zebrafish are capable of learning very well during their active phase during the day, but learn very poorly at night during their sleep or quiet phase.”

Roman’s team at UH for this breakthrough study included Gregory M. Cahill, associate professor of biology and biochemistry, and two of their students and research assistants, Oliver Rawashdeh and Nancy Hernandez de Borsetti.
© University of Houston 2007