Circadian System of Diurnal Rodents: Integrated Physiological/Behavioral Approach

日常生物计时，最好的反映在感知 就人类的“时差”或轮班工作疾病而言， 由神经起搏器（SCN）和 环境同步剂。起搏器自主 驱动依赖于生物化学、生理和行为 常数条件下具有自由运行的昼夜节律周期的函数 环境条件接近但不完全是24小时， 环境夹带剂或同步剂校正相位， 和频率与当地时间的关系。许多哺乳动物 昼夜节律的研究，特别是生理方面的研究， 仅限于实验室大鼠和金黄仓鼠。以试图 区分昼夜节律“布线”之间的差异， 哺乳动物和更知名的夜间哺乳动物，这项研究将检查 三种昼行性物种在连续阶段的关键问题 包括来自环境的感官输入 对于娱乐，SCN节律的生理特性 生成器和行为输出。 生理和行为昼夜输出测量将被 在这三种白天活动的啮齿动物中使用，以澄清昼夜节律 白天活动的哺乳动物的调节。13岁的羚羊地松鼠 以黄鼠、花栗鼠为模型 物种，以尽量减少长期以来阻碍 昼夜行为功能的研究进展 哺乳动物，并评估昼夜变化的跨度， 在生态上有很大差异的沙漠、草原和森林物种。 问题将包括轻采样过程中夹带 实验室和现场，环境温度的作用以及 昼夜节律功能中的循环体温，以及 的“光模仿”相位响应曲线系统（PRC），通过使用 脑室内注射卡巴胆碱;关键酶的分布 SCN神经肽（NP-II、VIP、SS、NPY）将通过 免疫细胞化学方法加上计算机图像处理， 共定位免疫反应性的定量测定。 最后，在体外和体内记录SCN的节律输出， 相对于其他脑区也将被研究。数据 可以作为一个有用的模型，以更好地了解 哺乳动物昼夜节律系统的功能，以及更多 通常是为了设想相对简单的 SCN的神经元回路能够控制对比 昼夜节律行为模式。

Daily biological timekeeping, best reflected in the perception of lay persons in terms of human "jet-lag" or shift-work maladies, is regulated by a composite interaction of neural pacemaker (SCN) and environmental synchronizing agents. The pacemaker autonomously drives dependent biochemical, physiological and behavioral functions with free-running circadian period under constant environmental conditions close to but not exactly 24-hours, while the environmental entraining or synchronizing agent corrects phase and frequency of the pacemaker to local time. Much mammalian circadian research, particularly the physiological aspect, has been limited to laboratory rats and golden hamsters. In an attempt to distinguish differences between the circadian "wiring" of diurnal mammals and better known nocturnal mammals, the study will examine selected key issues for three diurnal species in successive stages of circadian function including sensory input from the environment for entertainment, physiological properties of the SCN rhythm generator, and behavioral output. Physiological and behavioral circadian output measurements will be employed in these three diurnal rodents to clarify circadian regulation in day-active mammals. The antelope ground squirrel, 13- lined ground squirrel, and eastern chipmunk were chosen as model species to minimize operational problems that have long hindered progress of research on circadian behavioral function in diurnal mammals, and also to assess circadian variation span in ecologically widely divergent desert, prairie, and forest species. Issues will include the light-sampling process for entrainment in lab and field, the role of environmental temperature as well as cyclic body temperature in circadian function, and the delineation of a "light-mimicking" phase response curve system (PRC) by use of intraventricular injection of carbachol; the distribution of key SCN neuropepetides (NP-II, VIP, SS, NPY) will be determined by immunocytochemical methods plus computerized image processing for quantitative determination of co-localized immunoreactivity. Finally, in vitro and in vivo recording of SCN rhythmic output relative to other brain areas will also be investigated. The data may serve as a useful model for better understanding the functioning of diurnal circadian systems of mammals, and more generally for envisioning the means by which the relatively simple neuronal circuitry of the SCN is able to control contrasting nocturnal and diurnal circadian behavior modes.