Tuesday, February 12, 2008

How Our Bodies Keep Time

Our alarm clocks may spring forward on March 9, but our biological clocks may take longer to adjust. That’s because our internal clocks are so tightly wound to many physiological and behavioral processes.

Researchers have learned that circadian rhythms—the 24-hour cycles that keep our bodies on time—are involved in sleep, weight gain, mood disorders, and a variety of diseases. Now, they’ve made remarkable strides in identifying genes and neural pathways involved in regulating our internal clocks. Building on this bed of research could lead to new treatments for insomnia, jet lag, depression, obesity, and other disorders.

Recent advances in circadian rhythms research follow. The National Institute of General Medical Sciences, a component of the National Institutes of Health, supported these basic research studies and supports others on circadian rhythms research.

Gaining Weight? Check Your Internal Time

Recent findings suggest that circadian rhythms are intricately tied to weight gain. When Carla Green and her collaborators at the University of Virginia fed high-fat diets to mice with and without a protein involved in circadian rhythms, they found that the mice lacking the protein gained only a modest amount while the mice with the protein nearly doubled their body weight. The findings suggest that circadian rhythms regulate metabolic processes involved in diet-induced weight gain.

Clock in a Box

Carl Johnson and colleagues at Vanderbilt University have reconstituted a circadian clock in vitro using three proteins. The synthetic clock follows a 24-hour rhythm, and it maintains this cycle over a range of temperatures—a defining, but poorly understood characteristic of circadian rhythms. The advance offers an unprecedented opportunity to study the mechanisms of internal clocks, the role of temperature in regulating daily cycles, and even the evolution of human circadian rhythms.

Single Change Starts the Clock

In a surprising finding, Paolo Sassone-Corsi of the University of California-Irvine and colleagues found that a single amino acid change in a protein triggers a chain of genetic events involved in internal timekeeping. If the modification is impaired, it could disrupt the cascade and serve as the underpinning of circadian rhythms-related ailments. The amino acid also could be a novel target for drug compounds regulating body clocks.

Adapted from materials provided by NIH/National Institute of General Medical Sciences, via Newswise.
Posted by Ajay :: 5:14 PM :: 0 comments

Post a Comment

---------------oOo---------------