Murphy P J, Campbell S S
Department of Psychiatry, New York Hospital-Cornell Medical Center, White Plains 10605, USA.
J Clin Neurophysiol. 1996 Jan;13(1):2-16. doi: 10.1097/00004691-199601000-00002.
Virtually all organisms have developed an internal timing system capable of reacting to and anticipating environmental stimuli with a program of appropriately timed metabolic, physiologic, and behavioral events. The predominant biological rhythms coincide with the geophysical cycle of day and night-the circadian rhythms. The suprachiasmatic nuclei comprise the primary pace-maker in mammals, exhibiting the properties fundamental to a rhythm-generating structure. This article summarizes recent research that has elucidated mechanisms of signal transduction within the circadian system. The roles of various neurochemicals and hormones in transmitting the circadian timing signal are described. Properties of the circadian system, including photic and nonphotic entrainment, phase response curves, masking, and the intrinsic variability in the system are discussed.
几乎所有生物体都已发展出一种内部计时系统，该系统能够通过适时安排新陈代谢、生理和行为活动程序来对环境刺激做出反应并进行预测。主要的生物节律与昼夜的地球物理循环相一致——即昼夜节律。视交叉上核是哺乳动物的主要起搏器，具有节律产生结构的基本特性。本文总结了近期阐明昼夜节律系统内信号转导机制的研究。描述了各种神经化学物质和激素在传递昼夜节律信号中的作用。讨论了昼夜节律系统的特性，包括光和非光的同步化、相位响应曲线、掩蔽以及系统内的固有变异性。
