The effects of anesthetics on the circadian rhythm of rats and mice

我们研究了吸入麻醉剂异氟醚和苯二氮卓三唑仑对大鼠和小鼠昼夜节律的影响。在不同时期吸入异氟醚4小时和8小时后，大鼠的昼夜运动活动和视交叉上核（SCN）的mPerl mRNA表达时间均未发生变化。然而，在麻醉期间，SCN中mPerl mRNA信号水平明显升高。结果提示异氟醚影响了mPerl mRNA的表达机制。尽管之前有报道称，三唑仑改变了仓鼠的昼夜节律，但大鼠的昼夜节律运动活动并未发生变化。然而，给药三唑仑降低了大脑皮层的mperl mRNA水平，但在SCN中没有。GABA_A受体抑制剂PTZ可提高LD和DD大鼠大脑皮层mPerl mRNA表达水平。Peri也被认为在大脑皮层中有节奏地表达。这一结果表明，三唑仑可能会破坏这种节律。在目前的研究中，异氟醚和三唑仑不影响昼夜节律起搏器的阶段。然而，mPerl的表达水平明显改变，这表明这些药物影响了昼夜节律时间保持机制和另一个时钟相关基因的昼夜节律表达。

We investigated the effects of inhalational anesthetics Isoflurane and benzodiazepine Triazolam on the circadian rhythm of rats and mice.During and after 4 or 8 hours inhalation of Isoflurane at various periods, rats did not show the shift of circadian locomotor activity or the timing of mPerl mRNA expression in the suprachiasmatic nucleus (SCN). However, the level of mPerl mRNA signal in the SCN significantly increased during the anesthesia. The findings suggest that Isoflurane affect the expression mechanism of mPerl mRNA.In spite of previous reports that Triazolam shifts the circadian rhythm of hamsters, rats did not show the change in circadian locomotor activity. However, the administration of Triazolam decreased the level ofmPerl mRNA in the cerebral cortex but not in the SCN.GABA_A receptor inhibitor PTZ increased the level of mPerl mRNA in the cerebral cortex both in LD and DD condition.Peri is also known to be expressed rhythmically in the cerebral cortex. This results suggest that Triazolam may disrupt this rhythm.In the present studies, Isoflurane and Triazolam do not affect the phase of the circadian pacemaker. However, the expression level of mPerl altered significantly, which suggest the effect of these drugs on the circadian time keeping mechanism and the circadian expression of another clock-related genes.