Effect of chronic mild stress on circadian rhythms in the locomotor activity in rats
Effect of chronic mild stress on circadian rhythms in the locomotor activity in rats
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DOI：
10.1016/0091-3057(95)02173-6
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发表时间：
1996-05-01
影响因子：
3.6
通讯作者：
Papp, M
中科院分区：
文献类型：
--
作者：
Gorka, Z;Moryl, E;Papp, M
本研究的目的是评估慢性轻度应激（CMS）程序，作为一个现实的抑郁症动物模型，是否影响大鼠的自发活动的节奏。从最佳拟合的余弦函数曲线估计节律参数（周期、中位、振幅、峰值相位和节律百分比）。周期是长度，mesor是平均水平，振幅（A）是程度，acrophase是节奏的时间;节奏百分比代表通过余弦回归估计的变异性，并表示为原始数据总变异性的百分比。在实验的13周期间，将动物保持在12 L：12 D循环中，并在前4周进行CMS。第5周，大鼠置于24 h/d的持续光照下（LL），第9周置于持续黑暗下（DD）。在LD 12：12中，与对照相比，CMS使暗相中的活性降低约50%（p < 0.01），并且不改变亮相中的活性，导致24小时活性降低约40%。CMS组和对照组的活动日变化幅度与0相比差异显著（p（A = 0）<0.0001），节律百分比在40-75%之间。CMS大鼠的昼夜节律（以24 h为周期）的平均值和振幅显著低于对照组（P < 0.001）。在LL中，在主观黑暗阶段，两组的活动减少约50%。另一方面，在主观光照阶段，仅CMS大鼠的活动减少。CMS和对照组大鼠的节律百分比分别为30%和58%，两组的中幅值、振幅和顶相值具有高度统计学差异。在DD中，CMS组的活动在主观暗相和亮相均具有统计学显著性降低。与来自LL的结果相反，来自DD的余弦曲线类似地相对于主观明暗周期移位。恢复LD周期后，两组的24小时活动水平在第13周变得相等，但两组之间的亮相和暗相差异仍有统计学意义（p < 0.05）。目前的结果表明，CMS施加明显的和长期的紊乱的昼夜节律的运动活动的大鼠。
The purpose of this study was to assess whether the chronic mild stress (CMS) procedure, as a realistic animal model of depression, affects the rhythms of the locomotor activity in rats. Rhythm parameters (period, mesor, amplitude, acrophase, and percent rhythm) were estimated from the best-fitted cosine function curves. Period is the length, mesor is the mean level, amplitude (A) is the extent, acrophase is the timing of the rhythm; percent rhythm represents the variability estimated by the cosine regresion and expressed as a percentage of the total variability of raw data. The animals were kept on the 12 L:12 D cycle during 13 weeks of the experiment and subjected to CMS for first 4 weeks. In week 5 the rats were under the constant light for 24 h a day (LL), and in week 9, under the constant darkness (DD). In LD 12:12 CMS decreased the activity in the dark phase by approximately 50% (p < 0.01) and did not change the activity in the light phase, resulting in a drop of the 24 h activity by about 40% in comparison to controls. The amplitude of diurnal variations of the activity was highly statistically different from zero at p(A = 0) < 0.0001,and the percent rhythm was in range of 40-75% in both the CMS and control groups. The mesor and the amplitude of the diurnal rhythm (with a period of 24 h) in the CMS rats were significantly (p < 0.001) lower than those in the control. In LL, the activity of both groups was diminished about 50% during the subjective dark phase. On the other hand, in the subjective light phase the activity of CMS rats only was diminished. The percent rhythm for the CMS and control rats was 30 and 58%, respectively, and values of mesor, amplitude, and acrophase for both groups were highly statistically different. In DD, the activity in the CMS group was statistically significantly lower in both the subjective dark and light phases. In contrast to the results from LL, the cosine curves from DD were similarly shifted in relation to the subjective light-dark cycle. After a restoration of the LD cycle the levels of the 24-h activity of both groups became equal in the 13th week, but the light and dark phase differences between the groups were still statistically significant (p < 0.05). The present results indicate that CMS exerts distinct and prolonged disturbances of the diurnal and circadian rhythms of the locomotor activity in the rats.