Recent awakenings in melatonin research.

Recent awakenings in melatonin research

Scientists investigating the brain hormone melatonin say new findings provide hope for people suffering from sleep disorders, seasonal depression or jet lag. Using radioactive markers, researchers have pinpointed the receptors where melatonin triggers its effects in the brain. The resulting map now allows them to study the hormone's biochemical activity and has already led to the development of synthetic compounds that can block or enhance melatonin's effects, says Margarita L. Dubocovich of Northwestern University Medical School in Chicago.

Researchers have long recognized melatonin -- produced in the pineal gland deep within the brain -- as a crucial player in the body's "biological clock." Melatonin production grinds to a halt each morning as the sunlight-detecting retina sends wakeup signals to the brain. At night its production resumes. Other cyclic functions -- such as core body temperatures and the release of hormones that influence sleep--are programmed in part by malatonin's peaks and troughs.

Luzindole, the first melatonin-related experimental drug tested in humans, "resets" the biological clock by blocking melatonin receptors. Scientists hope other drugs under development, such as long-lasting melatonin analogs, may correct poor sleep patterns in nightshift workers and in melatonin-depleted elderly. Treatment with natural melatonin has already proved useful against symptoms of jet lag, Dobocovich says. And related drugs may lessen symptoms of depression in people sensitive to wintertime decreases in sunlight.