PHYSIOLOGICAL SUBSTRATES OF A CIRCADIAN OSCILLATOR

下丘脑视交叉上核(SCN)是内源性的 振荡器在发电中起着明确的、关键的作用 以及每日(昼夜)生理振荡的夹带， 哺乳动物的新陈代谢和行为。我们广泛的研究目标是 了解分子、细胞和神经生理机制 SCN保留24小时的时间。待研究的模式物种为 老鼠。SCN起搏器在下丘脑脑片中完好无损地存活 在那里它可以被旨在解剖细胞的实验所访问 机械装置。我们的方法学方法结合了脑片培养和 测量昼夜节律的传统神经生理学技术 神经元活动节律和测定周期的生化分析 核苷酸水平、酶活性和蛋白质的磷酸化。 目前的建议是根据我们的发现自然地发展出来的 通过影响cAMP或cAMP的治疗可以重置脑片的节律 CGMP途径。此外，起搏器底物正在改变，因此 在捐献者的日子里，cAMP和cGMP或高K(O)可以重置节律 在捐赠者之夜。我们的具体目标包括：a)更充分地 探索cAMP在SCN功能中的作用)(通过检测cAMP水平 在SCN内的作用，调节cAMP的酶的活性， 褪黑素对cAMP效应的调节及cAMP的参与 相移中的刺激磷酸化，以及新的参与 CAMP刺激中的蛋白质合成)；b)检查 CGMP类似物在夜间的作用(通过检测cGMP的特异性 刺激，去极化刺激对cGMP水平的影响 确定蛋白激酶抑制剂在夜间是否有效)； 以及c)确定SCN下的其他第二信使通路 起搏器(通过探索潜在的、可能是互动的)案例角色 和磷脂代谢物)。因为SCN整合了大多数昼夜节律 行为和代谢变化，这项研究与 了解许多大脑和代谢功能障碍，包括某些 精神疾病的形式。

The suprachiasmatic muclei (SCN) of the hypothalamus are endogenous oscillators that serve a well-defined, critical role in the generation and entrainment of the daily (circadian) oscillations of physiology, metabolism and behavior of mammals. Our broad research objective is to understand the molecular, cellular and neurophysiological mechanisms by which the SCN keep 24 hr time. The model species to be studied is the rat. The SCN pacemaker survives intact in the hypothalamic brain slice where it is accessible to experiments aimed at dissecting cellular mechanisms. Our methodological approach combines brain slice culture with conventional neurophysiological techniques that measure the circadian rhythm of neuronal activity nd biochemical analyses that measure cyclic nucleotide levels, enzyme activities and proteins phosphorylated. The present proposal develops naturally from our finding that the SCN rhythm can be reset in the brain slice by treatments affecting cAMP or cGMP pathways. Further, the pacemaker substrates are changing so that the rhythm is reset by cAMP in the donor's days, and by cGMP or high K+(o) during the donor's night. Our specific aims include: A) to more fully explore the role of cAMP in SCN function )(by examining the level of cAMP action within the SCN, the activity of enzymes regulating cAMP, regulation of the cAMP effect by melatonin, the involvement of cAMP stimulated phosphorylation in phase-shifting, and the involvement of new protein synthesis in cAMP stimulation); B) to examine the nature of the effect of cGMP analogs at night (by examining the specificity of cGMP stimulation, the effect of depolarizing stimuli on cGMP levels, and determining whether protein kinase inhibitors are effective at night); and C) to identify other second messenger pathways underlying the SCN pacemaker (by exploring potential, possibly interactive, roles for Ca++ and phospholipid metabolites). Because the SCN integrates most circadian behaviors and metabolic changes, this Study has basic relevance to understanding many brain and metabolic dysfunctions, including certain forms of mental illness.