Rosenwasser A M
Department of Psychology, University of Maine, Orono 04469.
Pharmacol Biochem Behav. 1989 Jun;33(2):291-7. doi: 10.1016/0091-3057(89)90502-9.
This study examined the effects of the alpha 2-adrenergic agonist clonidine on free-running circadian activity rhythms in rats, using a dosing regimen similar to one previously shown to induce behavioral depression in the swim test. In constant light, clonidine consistently shortened the free-running circadian period, reduced circadian amplitude, and reduced the overall level of locomotor activity. These effects were reversed after the termination of clonidine treatment. In constant darkness, clonidine reduced circadian amplitude, but both increases and decreases in free-running period and activity level were observed. Clonidine-induced changes in free-running period and activity level were systematically related to individual differences in baseline activity in both constant light and constant darkness. These results demonstrate that clonidine can alter both the rhythmicity and the level of spontaneous activity, and are consistent with the hypothesis that monoaminergic systems may mediate relationships between behavioral state and circadian rhythmicity.
本研究使用一种给药方案，该方案类似于先前在游泳试验中显示可诱发行为抑郁的方案，研究了α2 - 肾上腺素能激动剂可乐定对大鼠自由活动昼夜节律的影响。在持续光照条件下，可乐定持续缩短自由活动昼夜周期，降低昼夜节律振幅，并降低运动活动的总体水平。可乐定治疗终止后，这些影响得到逆转。在持续黑暗条件下，可乐定降低昼夜节律振幅，但自由活动周期和活动水平出现增加和减少的情况均有观察到。在持续光照和持续黑暗条件下，可乐定引起的自由活动周期和活动水平变化与基线活动的个体差异存在系统性关联。这些结果表明，可乐定可改变节律性和自发活动水平，并且与单胺能系统可能介导行为状态与昼夜节律之间关系的假说一致。
