FUNCTIONAL-ANALYSIS OF CIRCADIAN PACEMAKERS IN NOCTURNAL RODENTS .5. PACEMAKER STRUCTURE - CLOCK FOR ALL SEASONS
FUNCTIONAL-ANALYSIS OF CIRCADIAN PACEMAKERS IN NOCTURNAL RODENTS .5. PACEMAKER STRUCTURE - CLOCK FOR ALL SEASONS
复制标题
DOI：
10.1007/bf01417860
复制
发表时间：
1976-01-01
期刊：
影响因子：
--
通讯作者：
DAAN, S
中科院分区：
文献类型：
--
作者：
PITTENDRIGH, CS;DAAN, S
这一系列的主要研究结果被整合在一个通用模型中。该模型指出，2个振荡器参与昼夜活动节律。这是由分裂现象推断出来的，已知这种现象发生在几种哺乳动物和鸟类中。本文描述了仓鼠在恒定光照下分裂的实验研究。当白足鼠从LL到DD（恒定暗）再到LD（光暗比）12 h：12 h时，双峰活动峰（LD）的两个分量在一段时间内可以在不同的频率（DD）上运行，表明双峰活动峰和分裂是基于同一个双振子系统。该模型假设存在两个振子或主振子群E和M，自发频率对光强度的依赖性相反。τ之间的相位关系（ψ EM）对光强度的依赖性和τ的依赖性（起搏器周期）对psi. EM的影响解释了昼夜节律起搏器的所有历史依赖性特征，以及τ的相互依赖性，PRC（相位响应变化）和τ-不稳定性该模型定性地适应τ的相互依赖性。和α。[活动时间]总结在Aschoff规则中。在模型中的主要直观元素被发现的计算机模拟的特点。讨论了模型与光周期季节变化的关系。一种起搏器，包括：两个振荡器相互作用，但分别与日出和日落耦合，增强了其适应季节变化的能力;两个振荡器可能涉及起搏器已知的区分昼长的能力。
The major findings of this series are integrated in a general model. This model states that 2 oscillators are involved in circadian activity rhythms. This is deduced by the splitting phenomenon, known to occur in several species of mammals and birds. The empirical regularities of splitting in hamsters exposed to constant illumination (LL) are described. When Peromyscus leucopus is transferred from LL to DD (constant dark) to LD (light-dark ratio) 12 h:12 h, the 2 components of the bimodal activity peak (in LD) can for some time run at different frequencies (in DD), suggesting that bimodality of activity peaks and splitting are based on the same 2-oscillator system. The model assumes the existence of 2 oscillators or principal groups of oscillators E and M, with opposite dependence of spontaneous frequency on light intensity. The dependence of the phase relationship (.psi.EM) between the 2 on light intensity and the dependence of .tau. (pacemaker period) on .psi.EM account for all the history-dependent characteristics of circadian pacemakers, and for the interdependence of .tau., PRC (phase response change) and .tau.-lability. The model qualitatively accomodates the interdependence of .tau. and .alpha. [activity time] summarized in Aschoff''s Rule. The major intuitive elements in the model were found to characterize a computer simulation. The relevance of the model to seasonal change in photoperiod is discussed. A pacemaker comprising .+-.2 oscillators mutually interacting but coupled separately to sunrise and sunset enhances its competence to accomodate to seasonal change; and 2 oscillators may be involved in the pacemaker''s known ability to discriminate between daylengths.