Abstract # 207:

Scheduled for Saturday, June 22, 2013 10:00 AM-10:30 AM: Session 25 (San Geronimo Ballroom C) Oral Presentation


A. J. Davidson
Morehouse School of Medicine, 720 Westview Dr SW, Atlanta, GA 30310, USA
     The daily alternation of light and dark represents a key context in which organisms evolved on our planet. This temporal world encouraged the development of internal timing mechanisms that would maximize efficient use of resources and avoidance of predation. Thus circadian rhythms represent the output of biological clocks that program physiological activity and behavior within the 24h day. Sleep/wake patterns, hormone secretion and most measurable biological variables exhibit daily maxima and minima, and these rhythms persist in the absence of external time cues. During shift work and after nighttime light exposure, lighting environments different from those in which we evolved, circadian disruption can occur which has been linked to sleep disorders, cancer and mood disorders. In this presentation we will introduce the concepts of circadian timing in mammals, and describe how rhythms are impacted by non-traditional lighting schedules. Further, we will explain how the immune system, a complex and rhythmic system which is involved in the pathogenicity of many diseases, exhibits striking changes in animals exposed to a variety of lighting cycles. These results suggest a potential underlying common cause for the wide variety of diseases more prevalent among shift workers, who represent more than 15% of the US working population.