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： 哪些哺乳动物的生理和行为会产生季节性变化 与不断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、毛足鼠和叙利亚仓鼠的反应， Mesocricetus auratus，到初夏的静态长短日照长度 和冬季。 拟议的实验描述了这些 反应因前一天暴露时间的长短而异。 积累中 有证据表明光周期系统的正常功能 只能通过逐步整合来准确评估 光周期时间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 广泛使用日长的自然渐进并评估变化 体重和性腺状况。 额外的实验模拟 直接与中间和逐渐相关的褪黑激素模式 改变患有神经损伤和其他疾病的动物的白天长度 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 逐渐减少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 内源间隔计时器的运行受日长的影响 早期开发经验丰富； 3）过去的褪黑激素暴露情况如何， 生殖状态和昼夜节律系统的夹带状态有助于 对当前褪黑激素信号的解释； 4) 是否是前一天 长度影响未来褪黑激素信号的产生或对 他们; 5）昼夜节律系统是否参与歧视 抑制刺激性褪黑激素信号。 提议的实验是 与了解人类心血管季节节律相关 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。 这个基本的 研究将增加有助于发展的文献体系 并测试针对情绪和睡眠障碍、时差反应的合理疗法 轮班工作。 最后，这些研究提供了有关如何 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，人类自行口服褪黑激素时可能会发生这种情况。