Circadian ocillation and mechanisms of c-fos mRNA in rat cortex

C-fos基因是一种受多种刺激作用且具有诱导性的癌基因。有报道称，c-fos可通过钙内流去极化或增加cAMP的方式在神经元中诱导。我们报道了它在大鼠大脑皮质中的表达呈现昼夜节律。并且表达呈现两种不同的模式。然后，我们研究了静脉麻醉剂异丙酚(2，6-二异丙基苯酚)抑制正常大鼠新皮质c-fos基因表达的作用，c-fos基因的表达在暗期前2小时开始增加，并在暗期后持续升高。同时，异丙酚可诱导丘脑中线核团c-fos基因的表达，一些苯二氮卓类麻醉药也可激活该核团。提示异丙酚的麻醉作用可能是通过激活丘脑中线核团实现的。我们还观察了异丙酚20 mg/kg和30 mg/kg给药对大鼠橄榄核和大脑皮质c-fos基因表达的影响。10 mg/kg剂量的丙泊酚不能诱导这些核团和皮质c-fos基因的表达，提示相对大剂量的异丙酚对这些核团有一定的影响。

c-fos gene is one of the oncogene which is responsible by many stimulus and is inducible. c-fos was reported inducing in neurons by depolarized with Ca influx or increasing of cAMP. We reported that it's expression showed circadian rhythm in the rat cortex. And the expression showed 2 different patterns. Then We investigated intravenous anesthetic Propofol (2, 6-di-isopropylpenol) suppressed the induction of c-fos mRNA in the rat neocortex which expression began to increase 2 hours before the dark period and remained elevated following the dark period in a normal rat. Simultaneously, administration of Propofol induce the expression of c-fos mRNA in the midline thalamic nuclei which is also activated by some benzodiazepine narcotic drugs. These indicate that narcotic action of Propofol will exhibit via activation of midline thalamic nuclei. We also investigate that c-fos mRNA expression in the olivary nucleus and cereberal cortex in administration of Propofol at the rate of 20 mg/kg or 30 mg/kg. Rate of 10 mg/kg do not induce the c-fos mRNA in these nucleus and cortex, suggest that comparative high dose administration of propofol have some affects for these nucleus.