Warren W S, Champney T H, Cassone V M
Department of Biology, Texas A & M University, College Station 77843-3258.
Physiol Behav. 1994 Jun;55(6):1091-9. doi: 10.1016/0031-9384(94)90392-1.
The mammalian suprachiasmatic nucleus (SCN) controls a wide variety of circadian behavioral and physiological processes. The specific motor output pathway(s) by which these diverse processes are controlled are unknown. The only established motor output of this system is the regulation of pineal melatonin synthesis via the sympathetic nervous system. It is therefore possible that other peripheral circadian rhythms are regulated similarly. To address this issue, body temperature (BT), general activity (GA), wheel-running activity (WR), and heart rate (HR) were recorded in laboratory rats, and the effects of SCN lesion (SCNX) and of pharmacological sympathectomy with guanethidine (GUAN) on these multiple circadian rhythms were determined. The SCNX abolished circadian patterns in all motor outputs, whereas sham animals showed robust rhythms in all measures. In contrast, guanethidine, which depleted peripheral but not central catecholamine content, selectively reduced HR circadian rhythmicity. Other rhythms (BT, GA, and WR) were unaffected. These results suggest that the SCN influences some peripheral targets via circadian regulation of the sympathetic nervous system, and other circadian outputs are regulated via different, unknown pathways.
哺乳动物的视交叉上核（SCN）控制着多种昼夜节律行为和生理过程。这些不同过程受控制的具体运动输出途径尚不清楚。该系统唯一已确定的运动输出是通过交感神经系统调节松果体褪黑素的合成。因此，其他外周昼夜节律也可能以类似方式受到调节。为解决这一问题，在实验室大鼠中记录了体温（BT）、总体活动（GA）、轮转活动（WR）和心率（HR），并确定了视交叉上核损伤（SCNX）和用胍乙啶（GUAN）进行药理学交感神经切除术对这些多种昼夜节律的影响。SCNX消除了所有运动输出中的昼夜节律模式，而假手术动物在所有测量指标中均表现出强烈的节律。相比之下，胍乙啶可耗尽外周而非中枢儿茶酚胺含量，选择性地降低心率的昼夜节律性。其他节律（BT、GA和WR）未受影响。这些结果表明，视交叉上核通过对交感神经系统的昼夜节律调节影响一些外周靶点，而其他昼夜输出则通过不同的未知途径进行调节。
