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的可诱导的癌基因。有报道c-fos可通过钙离子内流或cAMP增加引起的去极化而在神经元中诱导表达。我们报道了它在大鼠大脑皮层的表达呈现昼夜节律。表达呈现两种不同的模式。在此基础上，我们研究了静脉麻醉药异丙酚（2，6-di-isopropenol）对大鼠新皮层c-fos mRNA表达的抑制作用。同时，异丙酚诱导丘脑中线核c-fos mRNA的表达，这也被一些苯二氮类麻醉药物激活。提示异丙酚的麻醉作用是通过激活丘脑中线核团而发挥的。同时观察了异丙酚20 mg/kg和30 mg/kg剂量组大鼠橄榄核和大脑皮质c-fos mRNA表达的变化。10 mg/kg剂量组对上述核团和皮层c-fos mRNA无明显诱导作用，提示较高剂量异丙酚对上述核团和皮层有一定影响。

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.