噻环乙胺对大鼠不同脑区AC活性及cAMP含量的动态影响

Dynamic Effect of Tiletamine on AC Activity and cAMP Content in Different Brain Regions of Rats

为研究噻环乙胺对大鼠不同脑区腺苷酸环化酶(AC)活性及3’、5’-环腺苷酸(cAMP)含量的动态影响,将168只SD大鼠随机均分为2大组,分别测定脑AC活性及cAMP含量。每大组分为对照组和低、高剂量噻环乙胺组(腹腔注射30、60 mg.kg-1),每个剂量组又随机均分为麻醉组、恢复Ⅰ组和恢复Ⅱ组3个亚组。用放射免疫法测定脑组织AC活性、cAMP含量。结果表明:在两剂量的麻醉组不仅大脑皮层、丘脑的AC活性明显增强,而且上述脑区cAMP含量显著升高(与对照组相比,P<0.05)。在高、低剂量的恢复Ⅰ组上述两脑区的AC活性、cAMP含量均有不同程度的下降,其中高剂量组下降极显著(与麻醉组相比,P<0.01),恢复Ⅱ组明显下降(与麻醉组相比,P<0.01)。两剂量组对大鼠海马、脑干及小脑等脑区的AC活性、cAMP含量均无明显的影响。结果提示:AC、cAMP可能在噻环乙胺全麻作用产生的分子机理中发挥重要作用。噻环乙胺麻醉作用可能与提高大脑皮层、丘脑的AC活性,增加cAMP含量相关。

To observe the dynamic effects of tiletamine on AC activity and cAMP content in different brain regions of rats,168 SD rats were randomly divided into two groups,and the activity of AC and the cAMP content were measured respectively.Every group was divided into control group,high dose group（ip tilelamine 60 mg·kg-1） and low dose group（ip tilelamine 30 mg·kg-1）.The group was divided into three subgroups of maintenance of anesthesia,recovery from anesthesiaⅠand recovery from anesthesiaⅡ according to their anesthesia state.The activity of AC and the cAMP content were measured by radioimmunoassay（RIA）.The results of experiment showed that in the high and low dose maintenance of anesthesia groups,the AC ctivity in cerebral cortex and thalamus were obviously increased,and the cAMP content in above-mentioned regions were also obviously increased（compared with the control group,P〈0.05）.In the recovery from anesthesiaⅠgroups of high dose group and low dose group,the activity of AC and the cAMP content were decreased at different degree,and the high dose group was decreased obviously（compared with maintenance of anesthesia group,P〈0.01）.In the recovery from anesthesiaⅡ,they were obviously decreased（compared with maintenance of anesthesia group,P〈0.01）.Two dose groups have insignificant effect on the AC activity and the cAMP content in hippocampus,brain stem,and cerebellum.The results suggested that the AC activity and the cAMP content might play an important part in the molecular mechanisms of general anesthesia mediated by tiletamine.The anesthetic action of tiletamine might relate to enchance the activity of AC and increase the cAMP content in the cerebral cortex and thalamus.