amplitude of the scn clock enhanced by the behavioral activity rhythm振幅的视交叉上核时钟增强行为活动的节奏.pdf

Amplitude of the SCN Clock Enhanced by the Behavioral Activity Rhythm 1 1 1 1 Floor van Oosterhout , Eliane A. Lucassen , Thijs Houben , Henk Tjebbe vanderLeest , 1,2 1 Michael C. Antle , Johanna H. Meijer * 1 Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands, 2 Department of Psychology, Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada Abstract Circadian rhythms are regulated by the suprachiasmatic nucleus (SCN), a small structure at the base of the hypothalamus. While light effects on the SCN are well established, little is known of behavioral effects. This study elucidates direct modulating action of behavioral activity on the SCN by use of in vivo electrophysiology recordings, assessments of general locomotor behavior, and video-tracking of mice. The results show suppression of SCN neuronal activity by spontaneous behavior, the magnitude being dependent on the intensity, duration and type of behavioral activity. The suppression was moderate (32% of circadian amplitude) for low-intensity behavior and considerable (59%) for locomotor activity. Mild manipulation of the animals had reversed effects on the SCN indicating that different mechanisms are involved in the regulatory effect of spontaneous versus induced activity. The results indicate that exercise at the proper time of the cycle can boost the amplitude of the rhythm of the SCN clock itself. This has potentially bene