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

本实验观察了吸入麻醉药异氟醚和苯二氮卓仑对大鼠和小鼠昼夜节律的影响。在不同时间吸入异氟醚4或8小时后，大鼠的昼夜运动活动无明显变化，视交叉上核(SCN)mPerl m RNA表达的时程无明显变化。而在麻醉过程中，SCN内mPerl mRNA信号水平显著升高。这一发现提示异氟烷影响mPerl mRNA的表达机制。尽管此前有报道称三唑仑改变了金黄地鼠的昼夜节律，但大鼠的昼夜运动活动并没有发生变化。然而，给予三唑仑降低了大脑皮层mPerl mRNA的水平，但不降低了SCN的mPerl mRNA水平。GABA_A受体阻断剂PTZ增加了LD和DD条件下大脑皮层mPerl mRNA的水平。这一结果表明三唑仑可能会扰乱这种节律。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相位。然而，mPerl的表达水平发生了显著的变化，这表明这些药物对生物钟保持机制和其他时钟相关基因的昼夜表达的影响。

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.