Yanovski J A, Rosenwasser A M, Levine J D, Adler N T
Department of Psychology, University of Pennsylvania, Philadelphia 19104.
Brain Res. 1990 Dec 24;537(1-2):216-26. doi: 10.1016/0006-8993(90)90361-e.
To explore the multioscillator nature of the neurohumoral circuitry controlling the expression of circadian rhythmicity, rats' wheel running circadian activity rhythms were compared following sagittal knife cuts in the region of the suprachiasmatic nucleus (SSCN), following pinealectomy (PX) and following the combination of SSCN and PX. 25% of animals with knife cuts that passed through one SCN had disturbed running activity under constant illumination; rhythmic disturbances were seen neither in animals with sham knife cuts nor in rats with knife cuts on the midline or lateral to the SCN. Animals with both SSCN and PX were twice as likely to show severe rhythmic disruptions under free-running conditions as rats with SSCN and sham PX. Rats with PX and sham SSCN did not display disrupted activity rhythms. When animals with PX alone or SSCN alone were first observed under free-running conditions and then subjected to a second surgical procedure so that all animals underwent both PX and SSCN, all PX and most SSCN animals demonstrated coherent activity rhythms after the first operation, but 35% showed disruptions in circadian activity patterns only following the second surgery. The activity rhythms of rats with knife cuts placed either on the midline or lateral to the SCN did not deteriorate when combined with PX. Rats with coherent rhythms following knife cuts damaging one SCN had rhythm disruptions after the addition of PX. The effects of pinealectomy may indicate that the pineal gland plays a role in maintaining the coupling relationships in the multioscillator system controlling circadian activity rhythms. The results of this study also suggest that neither the direct commissural connection of the SCNs nor the humoral output of the pineal gland is indispensable for the expression of coherent circadian activity rhythms in the rat.
为了探究控制昼夜节律表达的神经体液回路的多振荡器特性，在视交叉上核（SSCN）区域进行矢状刀切、松果体切除（PX）以及 SSCN 与 PX 联合手术后，比较了大鼠的转轮昼夜活动节律。25%经过一个 SCN 的刀切动物在持续光照下的跑步活动受到干扰；假刀切动物以及 SCN 中线或外侧刀切的大鼠均未出现节律紊乱。在自由活动条件下，同时进行 SSCN 和 PX 的动物出现严重节律紊乱的可能性是仅进行 SSCN 和假 PX 大鼠的两倍。仅进行 PX 和假 SSCN 的大鼠未表现出活动节律紊乱。当单独进行 PX 或 SSCN 的动物首先在自由活动条件下观察，然后进行第二次手术，使所有动物都接受 PX 和 SSCN 时，所有 PX 和大多数 SSCN 动物在第一次手术后表现出连贯的活动节律，但只有 35%仅在第二次手术后出现昼夜活动模式紊乱。SCN 中线或外侧刀切的大鼠与 PX 联合时，其活动节律并未恶化。损伤一个 SCN 的刀切后具有连贯节律的大鼠在添加 PX 后出现节律紊乱。松果体切除的影响可能表明松果体在维持控制昼夜活动节律的多振荡器系统中的耦合关系中起作用。本研究结果还表明，SCN 的直接连合连接和松果体的体液输出对于大鼠连贯的昼夜活动节律表达都不是必不可少的。
