Action potential firing rhythms in the suprachiasmatic nucleus of the diurnal grass rat, Arvicanthis niloticus
Action potential firing rhythms in the suprachiasmatic nucleus of the diurnal grass rat, Arvicanthis niloticus
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DOI：
10.1016/j.neulet.2022.136954
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发表时间：
2022-11-14
影响因子：
2.5
通讯作者：
Ikeda，Masayuki
中科院分区：
文献类型：
--
作者：
Morioka，Eri;Miyamoto，Tsubasa;Ikeda，Masayuki
在哺乳动物中，日常生理活动是由位于下丘脑视交叉上核（SCN）的中枢昼夜节律起搏器调节的。近年来，越来越多的研究利用昼行草鼠来分析昼夜行为的神经机制。然而，SCN神经元的自发动作电位放电节律尚未在昼夜草大鼠中清楚地证明。因此，本研究探讨细胞外单单位记录SCN神经元在急性下丘脑切片ofArvicanthis niloticus（尼罗草大鼠）。研究结果发现，昼夜节律放电频率最高的时刻出现在黄昏（ZT 10-12时为6.4 Hz），其次是黎明（ZT 0 -2时为5.6 Hz），最低的时刻出现在半夜（ZT 14 -16时为3.6 Hz）。从一个单独的动物组的运动活动记录表明，在本研究中使用的实验室殖民地的尼罗河草大鼠显示昼夜行为，符合大黄昏峰下12：12小时的光暗周期和双峰节律下恒定昏暗的红光。因此，在尼罗草大鼠中观察到SCN放电频率和自发活动水平之间的正相关性。以前，在SCN神经元的动作电位放电的行为耦合已建议在体内记录，而本研究表明，在草大鼠SCN神经元的双峰放电节律的维持可以持续至少一天在体外。
In mammals, daily physiological activities are regulated by a central circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Recently, an increasing number of studies have used diurnal grass rats to analyze neuronal mechanisms regulating diurnal behavior. However, spontaneous action potential firing rhythms in SCN neurons have not been demonstrated clearly in diurnal grass rats. Therefore, the present study examined extracellular single-unit recordings from SCN neurons in acute hypothalamic slices ofArvicanthis niloticus(Nile grass rats). The results of this study found that circadian firing rhythms with the highest frequency occurred at dusk (6.4 Hz at zeitgeber time (ZT)10–12), while the secondary peak occurred at dawn (5.6 Hz at ZT0-2), and the lowest frequency took place in the middle of the night (3.6 Hz at ZT14-16). Locomotor activity recordings from a separate group of animals demonstrated that the Nile grass rats of the laboratory colony used in this study displayed diurnal behaviors that coincided with large crepuscular peaks under 12:12 h light–dark cycles and bimodal rhythms under constant dim red light. Thus, a positive correlation between SCN firing frequencies and locomotor activity levels was observed in the Nile grass rats. Previously, behavioral coupling of action potential firings in SCN neurons has been suggested byin vivorecordings while the present study demonstrates that the sustenance of bimodal firing rhythms in grass rat SCN neurons can last at least one dayin vitro.