Light may modulate seratonin levels, study finds

17 Jun 2002

Exposure to bright light could be used as a kind of "drug" to alter the chemical activity of the brain. In a letter in the 9 January 9 issue of Nature, Fred W. Turek and colleagues at the Center for Circadian Biology and Medicine at Northwestern University describe experiments with hamsters in which the effects of serotonin are blocked by exposure to a two-hour pulse of light.

Research has shown that serotonin plays a role in regulating circadian rhythms and also in regulating moods. When given to hamsters at a certain time of day, it normally advances the biological clock. But when combined with the exposure to light, the advances were considerably attenuated or completely blocked.

This suggests that light plays a role in modulating the activity of neurons in the brain that respond to serotonin. These changes "could have important implications for the use of light as a 'drug' to alter neurochemical activity in the brain," the researchers conclude.