Age-related circadian disorganization caused by sympathetic dysfunction in peripheral clock regulation

Aging decreases day-night fluctuations of physiological functions in our body including sleep-wake cycle. Time-keeping mechanism of our clock is event of “entrainment” to daily environmental cues such as light-dark and food. Shigenobu Shibata from Waseda University in Japan and colleagues investigated a hallmark of age-related change of the circadian clock entrainment system by using non-invasive mouse peripheral clock imaging method. They found that weakened sympathetic regulations in aged animals attenuated internal clock information signaling between central and peripheral clocks, and caused the reduction of light-or exercise/stress-induced clock entrainment, but improved food-induced entrainment. Because circadian clock has an important role for homeostasis, investigating properties of entrainment ability will help us to find good medication strategy for age-related decline of physiological function.