鞘内注射育亨宾对异氟烷镇痛作用的影响

The effect of intrathecal injection with yohimbin on the analgesia of isoflurane

目的观察鞘内注射育亨宾(Yohimbin,Y)对异氟烷(Isoflurane,Iso)镇痛作用的影响,探讨脊髓α2受体与异氟烷镇痛作用的关系。方法腹腔注射异氟烷建立镇痛模型,用甩尾法和扭体法观察鞘内注射α2受体阻断药育亨宾对异氟烷镇痛小鼠甩尾潜伏期(tail-flick latency,TFL)和扭体次数的影响。结果单独腹腔注射异氟烷0.3 ml/kg可产生明显镇痛作用(P<0.01);单独鞘内注射5μg或15μg的育亨宾对清醒小鼠TFL和扭体次数均无明显影响(P>0.05);2药合用组可缩短异氟烷镇痛小鼠的TFL(P<0.01),但对异氟烷镇痛小鼠的扭体次数无明显影响(P>0.05)。结论异氟烷对热刺激的镇痛作用与脊髓α2受体有关,而对化学性刺激的镇痛作用与脊髓α2受体关系不大。

Objective To observe the effect of intrathecal injection with yohimbin on the analgesia of isoflurane and investigate the relation between α2 - adrenoceptor in the spinal cord and the analgesia of isoflurane. Methods The analgesic model was established by intraperitoneal injection of isoflurane in mice. Analgesia tests were investigated with warm water tail - flick test and acetic - induced writhing test. The effect of intrathecal with α2 - adrenocerptor antagonist yohimbine （5 μg and 15 μg） on tail -flick latency （TFL） and the writhing times of the analgesic model was studied. Resuits Significant analgesia effect was observed following single isoflurane injection, i.p. （P 〈 0.01 ）. Intrathecal injection of α2 -adrenocerpto antagonist yohimbine （5 μg and 15μg） alone had no effect on awakening mice from TFL and on writhing times （P 〉 0.05）. Intrathecal injection with either dose of yohimbin reduced the TFL of the analgesic models （P 〈 0.01 ）, though, no significant effect on the mouse writhing times was observed （P 〉 0.05）. Conclusion Analgesia of isoflurane on the physical pains caused by thermal irritation is related to α2 - AR in the spinal cord, while there may be no relation between α2 - AR in the spinal cord and the analgesia of isoflurane on the pains resulting from chemical irritation.