Dissociation of motor activity circadian rhythm in rats after exposure to LD cycles of 4-h period.
Dissociation of motor activity circadian rhythm in rats after exposure to LD cycles of 4-h period.
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暴露于 4 小时 LD 周期后大鼠运动活动昼夜节律的分离。
DOI：
10.1152/ajpregu.1997.272.1.r95
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
A. Díez
中科院分区：
文献类型：
--
作者：
Joan Manel Vilaplana;T. Cambras;A. Díez
在30天内，Wistar大鼠每天接受6次暗脉冲（T4周期；3小时光照，1小时黑暗），以研究将其运动活动节律分离为不同昼夜节律成分的可能性。研究人员使用了雌雄大鼠，其中一半被切除了松果体，以检查松果体对夹带过程的影响。结果表明，当大鼠维持T4时，其运动活动存在4小时节律。大鼠在黑暗阶段表现出预期活动，表明运动活动成分实际上被外部光/暗（LD）周期所束缚。大鼠在T4后持续处于黑暗状态，一些来自黑暗阶段的运动活动成分在不同的昼夜周期内自由运行数天。这表明运动活动模式是由几个昼夜节律振荡器产生的。此外，在恒定光照条件下施用T4后，运动活动的自由跑动成分比恒定黑暗条件下施用T4时更为明显。这些结果支持了一个假设，即大鼠的昼夜节律系统是由几个昼夜节律振荡器组成的，它们的耦合程度取决于光照条件。在恒定的光线下，明亮的光线可能会抑制系统内的内部耦合，使其随后更容易受到T4周期的影响。切除松果体和假手术动物之间没有差异，尽管雌性对T4周期比雄性更敏感。
For > 30 days Wistar rats were subjected to six dark pulses per day (T4 cycles; 3 h light, 1 h dark) to study the possibility of dissociating their motor activity rhythm into distinct circadian components. Rats of both sexes were used, one-half of which were pinealectomized to examine the effect of the pineal gland on the entrainment process. Results show that when rats were maintained under T4 a 4-h rhythm in their motor activity was present. Rats showed anticipatory activity to dark phases, suggesting that the motor activity components are actually entrained to the external light/dark (LD) cycles. When rats were left under constant darkness after T4, some motor activity components coming from the dark phases free ran for several days with different circadian periods. This suggests that the motor activity pattern is generated by several circadian oscillators. Moreover, the free-running components of motor activity after T4 were more evident when T4 was applied after exposure to constant light than after exposure to constant darkness. These results support the hypothesis that the circadian system of the rat is formed by several circadian oscillators, whose degree of coupling depends on light conditions. In constant light, bright light may inhibit internal coupling within the system, making it subsequently more susceptible to the T4 cycles. No differences were observed between pinealectomized and sham-operated animals, although females were more sensitive to T4 cycles than males.