安氟醚对大鼠皮层、海马、脑干腺苷酸环化酶及磷酸二酯酶活性的影响

EFFECTS OF ENFLURANE ON THE ACTIVITY OF ADENYLATE CYCLASE AND PHOSPHODIESTERASES IN CORTEX HIPPOCAMPUS AND BRAIN STEM OF RATS

目的观察安氟醚麻醉后大鼠不同脑区、不同时期腺苷酸环化酶(Adenylatecyclase ,AC)及磷酸二酯酶(Phosphodisterase ,PDE)活性的动态变化,并探讨cAMP在其麻醉中的可能作用。方法SD大鼠40只,随机分成5组,每组8只,吸入1 5 %的安氟醚,分别在未吸入安氟醚时(对照组)、翻正反射即将消失时(诱导期组)、翻正反射消失后2min(麻醉期组)、翻正反射恢复即刻(恢复期组)和翻正反射恢复后1h(清醒期组)断头取脑。放射性同位素法测定大脑皮层、海马和脑干的腺苷酸环化酶及磷酸二酯酶活性。结果在皮层,与对照组相比,AC活性在诱导期时开始升高,麻醉期时及恢复期时明显高于对照组( P <0 0 5 ) ,清醒期时恢复至对照组水平;PDE活性在诱导期时和麻醉期时均低于对照组( P <0 0 5 )。在海马,与对照组相比,AC活性只在麻醉期时升高明显(P <0 0 5 ) ;PDE活性在诱导期时和麻醉期时下降明显(P <0 0 5 ,P <0 0 1)。在脑干,与对照组比,AC活性在诱导期、麻醉期和恢复期均高于对照组(P <0 0 5 ) ;PDE活性只在麻醉期下降显著,(P <0 0 5 )。结论安氟醚升高大脑皮层、海马及脑干的腺苷酸环化酶活性,降低了磷酸二酯酶活性,从而增加了cAMP的含量,提示cAMP在安氟醚的全麻机制中可能发挥重要作用。

Objective To investigate the effects of enflurane on the activity of adenylate cyclase (AC) and phosphodiesterases(PDE) in cortex, hippocampus brain stem of rats, and to examine the role of cyclic adenosine monophosphate(cAMP) in the mechanism of enflurane anesthesia. Methods Fourty SD rats were divided randomly to 5 groups, each with 8 rats: control group (n=8), rats′righting reflex was about to lose (induction group, n=8), after losing righting reflex for 1 min (anesthesia group, n=8), righting reflex was about to recover (recovery group, n=8) and one hour after righting reflex recovery(aware group, n=8). The brain tissues were rapidly dissected into cerebrocortex and hippocampus and brain stem and kept for the assessment of adenylate cyclase and phosphodiesterases activity. Results At cerebrocortex, compared with that in control group, the activity of AC in induction group increased, and significantly increased in anesthesia group and recovery group (P<0.05), then recoved to level of control group in aware group.the activity of PDE in anesthesia group significantly decreased in induction and anesthesia groups(P<0.05). At hippocampus, the activity of AC in anesthesia group were significantly higher than that in control group (P<0.05); while the activity of PDE in induction group and anesthesia group was lower (P<0.05). At brain stem, compared with that in control group, the activity of AC in induction group and anesthesia group was significantly increased(P<0.05), the activity of PDE only in anesthesia group signficantly decreased(P<0.05). Conclusions Enflurane could increase AC activity and decrease PDE activity of cerebrocortex, hippocampus and brain stem of rats; which indicated that cAMP may play an important role in the mechanism of enflurane anesthesia.