Circadian or daily rhythms sculpt our responses to the environment. How flexible is the body system that controls our daily rhythms? Clearly circadian rhythms are strongly influenced by light:dark signals, and seasonal changes in day length. We will research the plasticity, or ability to change, in the mammalian circadian system. Circadian rhythms can be measured over many cycles in cultured tissues, such as the suprachiasmatic nuclei (SCN) in the brain, the master pacemaker for the circadian system in mammals, and also in several peripheral tissues, such as the heart, liver, or lung. Circadian rhythms in SCN and peripheral tissues can be measured by light emissions, or bioluminescence, from cultured tissues of a transgenic mouse, the mPer2Luc knockin mice. This project examines responses to altered duration of light changes in period or cycle length after altered length light:dark cycles and will determine the effects of exercise and thus sleep time. These studies will provide answers to fundamental questions about circadian rhythms in mammals. The project will determine if environmental changes alter the behavior of peripheral organs and the SCN when they are isolated in tissue culture and will determine if peripheral organs can also express plasticity of period induced by syncrhonization to varied light:dark-cycles. Finally, the project will deternine if exercise can slow the rate of re-synchronization of SCN and peripheral organs. These experiments will clarify the complex relationship between the environment, the SCN master pacemaker, and the slave oscillators in peripheral tissues. These studies will be conducted at an undergraduate college for women, with promising undergraduate women, many from under-represented minority groups, taking leadership roles. Students will be guided by the PI as they conduct research during the academic year and through summer internships. Participation in an active research lab will provide talented women encouragement and training as they begin scientific careers.
