Assessment of analgesic effect of general anesthetics by gene expression (c-fos)

本研究旨在观察氟烷对福尔马林致大鼠脊髓c-fos蛋白表达的影响，将大鼠随机分为5组：（1）对照组（n = 5）。(2)大鼠连续吹入1.1%氟烷。(3)大鼠连续吹入1.7%氟烷。(4)在福尔马林第1阶段反应期间，仅对大鼠吹入1.7%氟烷。(5)在对福尔马林的2相反应期间，仅用1.7%氟烷吹入大鼠，氟烷以剂量依赖的方式抑制c-fos蛋白表达。与对照组相比，第4组和第5组大鼠的c-fos蛋白表达均显著降低。然而，这些减少的幅度显着小于第3组大鼠。数据证实，氟烷抑制脊髓神经元对伤害性刺激的反应。他们还表明，氟烷能够抑制中枢致敏的诱导和维持。然而，在通过伤害性刺激建立中枢致敏之前和之后给予氟烷的条件下，可以获得最大抑制。

In the present study, the effect of halothane on formalin-induced c-fos protein expression in rat spinal cord was investigated.All rats received 5% formalin into the unilateral hind paws and then were randomly assigned into 5 groups as follows : (1) Control group. (2) The rats were continuously insufflated with 1.1% halothane. (3) The rats were continuously insufflated with 1.7% halothane. (4) The rats were insufflated with 1.7% halothane only during the phase 1 response to formalin. (5) The rats were insufflated with 1.7% halothane only during the phase 2 response to formalin.Halothane suppressed c-fos protein expression in a dose dependent manner. The c-fos protein expression of not only group 4 but also group 5 rats was significantly reduced compared with that of control rats. However, the magnitude of these reductions was significantly less than that of group 3 rats.The data confirm that halothane suppresses the spinal neuronal response to noxious stimulation. They also suggest that halothane is able to suppress both the induction and maintenance of central sensitization. The maximum suppression, however, may be obtained in conditions when halothane is administered both before and after the establishment of central sensitization by noxious stimulation.