TEMPORAL INTEGRATION OF PHOTOPERIODIC SIGNALS IN MAMMALS

哺乳动物光周期信号的时间整合

• 批准号: 6387954
• 负责人: MICHAEL R GORMAN
• 金额: $ 10.37万
• 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/6387954
• 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： 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。 先前研究 研究了西伯利亚仓鼠、太阳足鼠和叙利亚仓鼠的反应， 中仓鼠，以静态长和短日长的初夏 冬天，分别。 拟议的实验描述了这些 响应作为先前日长暴露的函数而不同。 积累 有证据表明光周期系统的正常功能 只能通过逐步和 持续变化的日长模式， 测量系统不断发展。 因此，所提出的实验使得 广泛使用日长的自然进展和评估变化 体重和性腺状况 其他实验模拟 直接的褪黑激素模式与中间和逐渐 改变具有神经病变和其他疾病的动物的日照长度 昼夜节律系统的操纵。 具体实验涉及1）是否 秋季体重的逐渐下降反映了对 逐渐减少的日长或内部定时的输出 由一个关键日长触发的机制; 2） 内源性间隔计时器运行的时间受日长的影响 在发育早期经历; 3）过去的褪黑激素暴露， 生殖状态和昼夜节律系统的夹带状态有助于 当前褪黑激素信号的解释; 4）前一天是否 长度影响未来褪黑激素信号的产生或对 他们;和5）是否昼夜节律系统参与区分 抑制刺激性褪黑激素信号。 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、抑郁和非精神病情绪状态。 这一基本 研究将增加一个文献的机构，有助于发展 测试情绪和睡眠障碍，时差反应， 轮班工作。 最后，这些研究提供了关于如何 季节性机制可能会对褪黑激素信号的非自然变化做出反应 例如可能发生在人类自我施用褪黑激素的口服剂量中。