Temporal Integration of Photoperiodic Signals in Mammals

哺乳动物光周期信号的时间整合

基本信息

批准号：
7793495
负责人：
MICHAEL R GORMAN
金额：
$ 22.3万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-04-20 至 2012-03-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): This project investigates the neuroendocrine mechanisms by which mammals generate seasonal variations in physiological and behavioral traits in synchrony with changing environmental conditions and the consequences of this variation for aging of circadian function. Studies in this area have examined responses of Siberian, Phodopus sungorus, and Syrian hamsters, Mesocricetus auratus, exposed to static long and short day lengths of early summer and winter, respectively. Accumulating evidence establishes that photoperiodic systems function markedly differently under natural conditions that incorporate the incrementally and continuously changing pattern of day lengths under which these systems evolved. An ecologically relevant understanding of these annual rhythms is particularly important clinically, as humans, like laboratory rodents, are commonly isolated from the yearly pattern of change in daylength, but the consequences of this deprivation have gone virtually unexamined. Specific experiments in hamsters address 1) whether under naturalistic conditions melatonin interacts endogenous temporal programs that mediate the transitions between photoperiodic states; 2) how the function of the circadian oscillator is regulated by seasonal photoperiods; and 3) how age-related deficits in circadian function can be retarded by photoperiodic manipulations. The proposed experiments are relevant to an understanding of the myriad human seasonal rhythms that have been previously documented (e.g., in cardiovascular disease, neurodevelopmental disorders, immune function, sleep duration, body weight, depression and nonpsychiatric mood states). Additionally, these studies will assess whether photoperiodic manipulations might be effective adjuncts to achieve rapid phase-shifting of human rhythms, and whether such manipulations have therapeutic value for disruptions of circadian rhythmicity in old age. Finally, these studies form a necessary information base to evaluate the potential physiological costs and benefits of artificial lighting regimes experienced by humans in modern society.

描述（由申请人提供）：该项目研究哺乳动物产生与环境条件变化同步的生理和行为特征季节性变化的神经内分泌机制，以及这种变化对昼夜节律功能衰老的影响。该领域的研究考察了西伯利亚仓鼠、Phodopus sungorus 和叙利亚仓鼠 Mesocricetus auratus 分别暴露于初夏和冬季的静态长日照和短日照下的反应。越来越多的证据表明，光周期系统在自然条件下的功能显着不同，这些系统在自然条件下不断变化的日长模式不断演化。对这些年度节律的生态相关理解在临床上尤其重要，因为人类（如实验室啮齿动物）通常与日长的年度变化模式隔离开来，但这种剥夺的后果几乎未经检验。在仓鼠身上进行的具体实验涉及：1）在自然条件下，褪黑激素是否与介导光周期状态之间转换的内源时间程序相互作用； 2）昼夜节律振荡器的功能如何受季节光周期的调节； 3）如何通过光周期控制来延缓与年龄相关的昼夜节律功能缺陷。拟议的实验与对先前已记录的无数人类季节性节律的理解相关（例如，心血管疾病、神经发育障碍、免疫功能、睡眠时间、体重、抑郁和非精神情绪状态）。此外，这些研究将评估光周期操作是否可能是实现人类节律快速相移的有效辅助手段，以及这种操作对于老年昼夜节律紊乱是否具有治疗价值。最后，这些研究形成了必要的信息库，以评估现代社会中人类经历的人工照明制度的潜在生理成本和益处。