TEMPORAL INTEGRATION OF PHOTOPERIODIC SIGNALS IN MAMMALS

哺乳动物光周期信号的时间整合

• 批准号: 6181736
• 负责人: MICHAEL R GORMAN
• 金额: $ 10.07万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6181736
• 关键词: behavioral /social science research tag; biological signal transduction; body weight; circadian rhythms; early experience; endocrine surgery; environmental adaptation; ethology; experimental brain lesion; hamsters; hormone regulation /control mechanism; male castration; melatonin; neuroendocrine system; photobiology; photostimulus; pineal body; seasons; suprachiasmatic nucleus

DESCRIPTION: This project investigates the neuroendocrine mechanisms by which mammals generate seasonal variations in physiological and behavioral traits in synchrony with changing environmental conditions. Prior studies have examined responses of Siberian, Phodopus sungorus, and Syrian hamsters, Mesocricetus auratus, to static long and short day lengths of early summer and winter, respectively. Proposed experiments characterize how these responses differ as a function of prior day length exposure. Accumulating evidence establishes that the normal functioning of photoperiodic systems can only be accurately assessed by incorporating the incrementally and continuously changing pattern of day lengths under which photoperiodic time measurement systems evolved. Accordingly, the proposed experiments make extensive use of naturalistic progressions of day lengths and assess changes in body weight and gonadal condition. Additional experiments simulate directly the melatonin patterns associated with intermediate and gradually changing day lengths in animals with neurological lesions and other manipulations of circadian systems. Specific experiments address 1) whether the gradual decrease in body weight in autumn reflects graded responses to progressively decreasing day lengths or the output of an internally timed mechanism triggered by a single critical day length; 2) how the speed at which the endogenous interval timer runs is influenced by the day lengths experienced early in development; 3) how past melatonin exposures, reproductive status and entrainment state of the circadian system contribute to the interpretation of current melatonin signals; 4) whether prior day lengths influence production of future melatonin signals or responses to them; and 5) whether circadian systems are involved in discriminating inhibitory from stimulatory melatonin signals. The proposed experiments are relevant to an understanding of human seasonal rhythms in cardiovascular disease, neurodevelopmental disorders, immune function, sleep duration,, body weight, depression and non-psychiatric mood states. This basic research will add to a body of literature contributing to the development and testing of rational therapies for mood and sleep disorders, jet lag, and shift work. Finally, these studies provide basic information about how seasonal mechanisms may respond to unnatural changes in melatonin signals such as may occur in humans self-administering oral dosages of melatonin.

描述：该项目通过以下方式研究神经内分泌机制 哪些哺乳动物在生理和行为上会产生季节性变化 与变化的环境条件同步的特征。先前的研究 研究了西伯利亚仓鼠、金黄地鼠和叙利亚仓鼠的反应， 从初夏的静态长日长和短日长 和冬天。拟议中的实验描述了这些 反应因前一天的暴露时间不同而不同。积累 有证据表明，光周期系统的正常功能 只有通过将增量和 光周期时间下日长的连续变化模式 测量系统得到了发展。因此，拟议的实验使 广泛使用自然主义的日长进度法，并评估变化 在体重和性腺状况下。附加实验模拟 直接与中间和逐渐相关的褪黑素模式 改变患有神经损伤和其他疾病的动物的日长 昼夜节律系统的操纵。具体实验解决1)是否 秋季体重的逐渐下降反映了对 逐渐递减的日长或内部定时的输出 由单个临界日长触发的机制；2)速度如何在 内生间隔计时器运行的时间受日长的影响 在发育早期经历；3)过去的褪黑素暴露是如何， 昼夜节律系统的生殖状态和夹带状态对 对当前褪黑激素信号的解释；4)前一天 长度会影响未来褪黑激素信号的产生或对 以及5)昼夜节律系统是否参与了区分 从刺激性褪黑素信号抑制。建议的实验是 与理解人类心血管疾病的季节性节律有关 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。这是基本的 研究将增加对发展做出贡献的文献主体 以及对情绪和睡眠障碍、时差以及 倒班工作。最后，这些研究提供了有关如何 季节性机制可能对褪黑激素信号的非自然变化做出反应 例如，在自我口服剂量的褪黑素的人类中可能会发生这种情况。