DALLAS—Researchers at UT Southwestern Medical Center have found that fluctuations in internal body temperature regulate the body’s circadian rhythm, the 24-hour cycle that controls metabolism, sleep and other bodily functions.
A light-sensitive portion of the brain called the suprachiasmatic nucleus (SCN) remains the body’s “master clock” that coordinates the daily cycle, but it does so indirectly, according to a study published by UT Southwestern researchers in the Oct. 15 issue of Science.
The SCN responds to light entering the eye, and so is sensitive to cycles of day and night. While light may be the trigger, the UT Southwestern researchers determined that the SCN transforms that information into neural signals that set the body’s temperature. These cyclic fluctuations in temperature then set the timing of cells, and ultimately tissues and organs, to be active or inactive, the study showed.
Scientists have long known that body temperature fluctuates in warm-blooded animals throughout the day on a 24-hour, or circadian rhythm, but the new study shows that temperature actually controls body cycles, said Dr. Joseph Takahashi, chairman of neuroscience at UT Southwestern and senior author of the study.