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Coupling of suprachiasmatic neuronal activity and peptide rhythms : pacemaker structures

视交叉上神经元活动与肽节律的耦合：起搏器结构

基本信息

批准号：
09670065
负责人：
HONMA Sato
金额：
$ 2.05万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

Present experiment was undertaken to clarify the coupling mechanisms of oscillatory neurons in the suprachiasmatic nucleus (SCN) which enables the pacemaker to drive a single stable circadian rhythm in the various physiological functions.1. Clock gene expression rhythms : Expression of clock genes, Clock and BMAL1, was examined by in situ hybridization. Clock and BMAL1 are strongly expressed in the SCN with a circadian fashion and the rhythms were 180 degree out of phase. To a 30 min light pulse given at various circadian times, BMAL1 expression was increased at all phases examined, while that of Clock, phase-dependently. The two genes may separately play one of the two roles in the light entrainment, parametric and non-parametric.2. AVP and VIP rhythms in the SCN slice : SCN slices cultured on a culture-insert membrane showed robust rhythms in AVP which phased to maternal AVP rhythm and desynchronized rhythms in VIP, but both rhythms damped out during the culture. The results suggest that AVP and VIP are driven by separate oscillators which are desynchronized during the culture.3. Coupling of neuronal oscillation and peptide rhythm generation : Single SCN neurons were cultured on a multi-electrode dish, and the circadian firing rhythms and peptide rhythms were compared. Significant circadian peptide rhythms were detected only in cultured dishes with synchronized neuronal rhythms, suggesting the peptide rhythm reflects the coupling of cellular oscillations.4. Synaptic coupling of individual SCN neuronal oscillator : The role of functional synapses in the coupling of cellular oscillations was studied by examining cross-correlation of spikes of a pair of SCN neurons which showed synchronized circadian firing rhythms and that with desynchronized rhythms. The result showed that an excitatory synaptic interaction with a short synaptic delay synchronizes the circadian firing rhythm oscillating neurons in the SCN.

本实验旨在阐明视交叉上核(SCN)内振荡神经元的耦合机制，使起搏器在各种生理功能中驱动单一稳定的昼夜节律。Clock基因表达节律：原位杂交检测Clock基因Clock和BMAL1的表达。CLOCK和BMAL1在SCN中呈昼夜节律性表达，节律呈180度反相。在不同的昼夜时间给予30min的光脉冲，BMAL1的表达在所检测的所有时相都增加，而CLOCK的表达则呈相位依赖性。这两个基因可能分别在光夹带中发挥参数和非参数两种作用之一。SCN切片中的AVP和VIP节律：在培养片上培养的SCN切片显示出强健的AVP节律和VIP的去同步化节律，但这两种节律在培养过程中都减弱了。结果表明，AVP和VIP是由分离的振荡器驱动的，这些振荡器在培养过程中是去同步化的。神经元振荡与肽节律产生的耦合作用：在多电极培养皿上培养单个SCN神经元，比较其昼夜放电节律和肽节律。仅在培养皿中检测到具有同步神经元节律的显著昼夜节律，提示该节律反映了细胞振荡的耦合。单个SCN神经元振荡器的突触耦合：通过检测表现同步昼夜节律和非同步节律的一对SCN神经元的棘波的相互关联，研究功能性突触在细胞振荡耦合中的作用。结果表明，具有短突触延迟的兴奋性突触相互作用使SCN内振荡神经元的昼夜放电节律同步。