In the young mice, the scientists found high levels of activity during the day and much lower activity levels during the night. In middle-aged mice, there was not nearly as large a difference in activity between the day and the night.
"In the middle-aged mice, they still have a circadian rhythm, but the amplitude is reduced," Block said. "During the nighttime, when electrical impulse activity levels are usually fairly low, the levels have increased. Thus, the difference between the highest levels of activity during the daytime and the lowest levels of activity during the nighttime is much smaller in the middle-aged mice."
Large numbers of people over the age of 65 regularly take sleeping pills, but the effects of taking such pills over many years is not known, said Colwell, who hopes the new research will lead to other options for getting a good night's sleep.
Colwell, Block and their team plan to pursue follow-up research on treatment options that could enhance the function of the circadian system with aging. They are studying the specific membrane channel changes in the SCN that are responsible for the electrical rhythm and also are looking at the circadian regulation of the heart and the mechanisms underlying neural activity rhythms in the SCN.
Their research could potentially lead to new ways of boosting the circadian output. It is possible, Colwell and Block said, that relatively simple approaches could be beneficial, such as exercising early in the morning, getting regular exposure to bright light, eating meals at consistent times and, when traveling, eating meals at the appropriate local time, regardless of whether one is hungry then.
Possible interventions may involve discovering ways to improve the sleep cycle of aging people and thei
|Contact: Stuart Wolpert|
University of California - Los Angeles