Honma Ken-ichi, Hashimoto Satoko, Nakao Mitsuyuki, Honma Sato
Department of Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
J Biol Rhythms. 2003 Jun;18(3):261-70. doi: 10.1177/0748730403018003008.
Entrainment of the circadian rhythm has 2 aspects, period and phase adjustments, which are established simultaneously in most nonhuman circadian systems. The human circadian system is unique in its functional structure in which 2 different subsystems are involved; one is the circadian pacemaker analogous to that located in the suprachiasmatic nucleus, and the other is the oscillatory system of unknown nature that drives the rest-activity cycle. The human circadian system shows the endogenous period very close to 24 h under entrainment and less sensitive to photic stimuli than under free running, which may explain stable entrainment in the real word where natural sun lights are unpredictable in terms of the intensity and time of appearance. On the other hand, nonphotic entrainment seems to play a significant role in phase adjustment of the human circadian system. Nonphotic zeitgebers initially directed to the rest-activity cycle may affect the circadian pacemaker through feedback and/or associated LD cycles.
昼夜节律的同步化有两个方面，即周期调整和相位调整，在大多数非人类昼夜节律系统中，这两个方面是同时建立的。人类昼夜节律系统在其功能结构上是独特的，涉及两个不同的子系统；一个是类似于位于视交叉上核的昼夜节律起搏器，另一个是性质未知的振荡系统，它驱动休息-活动周期。在同步化条件下，人类昼夜节律系统的内源性周期非常接近24小时，并且比自由运行时对光刺激的敏感性更低，这可能解释了在现实世界中自然阳光在强度和出现时间方面不可预测的情况下的稳定同步化。另一方面，非光同步化似乎在人类昼夜节律系统的相位调整中起重要作用。最初针对休息-活动周期的非光授时因子可能通过反馈和/或相关的明暗周期影响昼夜节律起搏器。
