Pathophysiology of Circadian and Ultradian Rhythm Disturbances on Behavioral and Visceral Functions, Stress Response, and Disease Susceptibility

摘要

U.S. military combat personnel will not always be able to maintain normal 24 hr schedules of work and rest. The work in this contract was directed toward modeling such non-24 hr environments in order to learn their consequences on physiological function, ability to preform a task, and susceptibility to succumbing to a disease process. To do this, we divided the work into 2 parts. The first of these used rodent models to study susceptibility to succumbing to disease. The first of these used a genetic model for heart disease -- the cardiomyopathic hamster. The second used activity-stress. In both models, we found that living in constant light, an extreme example of a non-24 hr environment, had a protective effect. Since one of the reasons for this effect related to a photoperiodic effect, we studied biological rhythms in hamsters living in long and short days and found that in contrast to those animals living in long days, those living in short days lost their circadian hormone rhythms.