Joy J E, Turek F W
Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208.
J Biol Rhythms. 1992 Spring;7(1):51-63. doi: 10.1177/074873049200700105.
Although light provides the primary signal for the entrainment of circadian pacemakers, a number of endogenous substances and pharmacological agents are also capable of resetting circadian pacemakers. Very little is known about the combined effects of photic and nonphotic agents on clock functions. We conducted a "double-pulse" experiment, in which two discrete stimuli are presented at different times within a single circadian cycle, to determine the combined effects of a 1-hr light pulse and injections of a benzodiazepine, triazolam, on the circadian rhythm of activity in the golden hamster. Our results suggest that, first, when given together as done in these experiments, the effects of triazolam and light are partially but not completely additive. Triazolam-induced phase advances appeared to make the effects of subsequent 1-hr light pulses more negative; phase delays were increased, and phase advances were decreased. Second, it appears that triazolam and light may alter the circadian pacemaker in very different ways, beyond the obvious difference in the shape of their phase response curves. The phase-shifting mechanics of the circadian system of the golden hamster appear to involve a longer response time to triazolam than to light pulses. Alternative possibilities to account for this difference are discussed.
虽然光为昼夜节律起搏器的同步提供主要信号，但一些内源性物质和药理制剂也能够重置昼夜节律起搏器。关于光和非光因子对生物钟功能的联合作用，人们所知甚少。我们进行了一项“双脉冲”实验，即在单个昼夜周期内的不同时间呈现两个离散刺激，以确定1小时光脉冲和注射苯二氮䓬类药物三唑仑对金黄仓鼠活动昼夜节律的联合作用。我们的结果表明，首先，如在这些实验中同时给予时，三唑仑和光的作用部分相加但不完全相加。三唑仑诱导的相位提前似乎使随后1小时光脉冲的作用更负；相位延迟增加，相位提前减少。其次，似乎三唑仑和光可能以非常不同的方式改变昼夜节律起搏器，这超出了它们相位响应曲线形状的明显差异。金黄仓鼠昼夜节律系统的相位移动机制似乎涉及对三唑仑的反应时间比对光脉冲的反应时间更长。文中讨论了解释这种差异的其他可能性。
