SUPRACHIASMATIC NUCLEI-NEUROBIOLOGY OF A CIRCADIAN CLOCK

昼夜节律是一种先天的 计时机构即，一种“生物钟”。“临床和 人类昼夜节律计时系统的实际重要性现在已经 已经被认识到，紊乱的时钟功能可能是 一些睡眠障碍和神经精神疾病的症状 疾病。 本研究计划的总体目标是 更好地了解内源性昼夜节律起搏器的性质 在哺乳动物下丘脑的视交叉上核（SCN）中。 在这场竞争中引入了两种新的研究策略 继续申请。 第一组拟议的实验将研究昼夜节律 无药物或病变干扰的起搏器 研究起搏器特性的自然遗传变异。 在初步数据中，两种近交系小鼠（BALB/cByJ和 C57 BL/6 J）表现出很大的株间差异 在他们的运动节奏的昼夜周期， 发现菌株（SEC/1 ReJ）具有运动节律， 与外界光暗周期的异常相位关系。 在所提出的实验中，首先， 这些菌株中的起搏器将通过表征 饮用和温度节律性，测试可能的 先前环境照明的后效，评估 睾酮的影响，以及构建起搏器“阶段- 响应曲线“第二，SCN的结构和功能 在这些菌株中，将通过描绘SCN结构进行比较， 绘制SCN神经递质的模式和 SCN突触接触，并确定SCN葡萄糖利用。 第三，这些菌株间的差异将被用作实验 神经移植和经典遗传实验中的工具。 第二组拟议的实验将研究昼夜节律 起搏器在更可控的设置，通过调查SCN， 一种体外制剂。 在初步数据中，SCN 在体外培养下丘脑切片数周， 辊管法 在拟议的实验中，首先，结构 并且培养切片的代谢的特征在于： 免疫细胞化学标记SCN神经元， 14 C标记的脱氧葡萄糖体外定量方法。 其次，将测试培养切片的昼夜节律性 通过使用22 Na+摄取、葡萄糖利用和精氨酸测定， 加压素释放

Circadian rhythmicity is the overt manifestation of an innate timekeeping mechanism i.e., a "circadian clock." The clinical and practical importance of the human circadian timing system has now been recognized, and disordered clock function may underlie the symptoms of a number of sleep disorders and neuropsychiatric illnesses. The overall objective of this research program is to better understand the nature of the endogenous circadian pacemaker in the suprachiasmatic nuclei (SCN) in the hypothalamus of mammals. Two new research strategies are introduced in this competing continuation application. The first set of proposed experiments will study the circadian pacemaker without the interference of drugs or lesions by investigating natural genetic variations in pacemaker properties. In preliminary data, two inbred strains of mice (BALB/cByJ and C57BL/6J) were found that exhibited a large interstrain difference in the circadian period of their locomotor rhythms and a single strain (SEC/1ReJ) was found with a locomotor rhythm that exhibited an anomalous phase relationship to the external light-dark cycle. In proposed experiment, first, the physiological properties of the pacemakers in these strains will be documented by characterizing drinking and temperature rhythmicity, testing for possible aftereffects of prior environmental illumination, assessing the influence of testosterone, and constructing pacemaker "phase- response curves." Second, the structure and function of the SCN in these strains will be compared by delineating SCN architecture, mapping the patterns of SCN neurotransmitters and the density of SCN synaptic contacts, and determining SCN glucose utilization. Third, these interstrain differences will be used as experimental tools in neural transplantation and classical genetic experiments. The second set of proposed experiments will study the circadian pacemaker in a more controlled setting by investigating the SCN as an in vitro preparation. In preliminary data, the SCN was cultivated as a hypothalamic slice for weeks in vitro using the roller-tube method. In proposed experiments, first, the structure and metabolism of the cultured slice will be characterized by immunocytochemically labeling SCN neurons and devising a quantitative 14C-labeled deoxyglucose method for in vitro use. Second, circadian rhythmicity of the cultured slice will be tested by using assays of 22Na+ uptake, glucose utilization, and arginine vasopressin release.