甲硫-脑啡肽对脾交感神经活动的双向调节作用

Bidirectional modulation of splenic sympathetic nerve activity by methionine-enkephalin

目的：观察第三脑室微量注射甲硫－脑啡肽（ｍｅｔ－ｅｎｋｅｐｈａｌｉｎ，Ｍｅｔ－Ｅｎｋ）对脾交感神经放电活动的影响。方法：用ｕｒｅｔｈａｎｅ和α－ｃｈｌｏｒａｌｏｓｅ麻醉的雄性Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ大鼠，于第三脑室分别微量注射Ｍｅｔ－Ｅｎｋ１μｇ和１００μｇ。结果：脾交感神经放电活动的双向调节作用，即微量注射１μｇＭｅｔ－Ｅｎｋ时脾交感神经冲动数会减少，而注射１００μｇＭｅｔ－Ｅｎｋ时脾交感神经冲动数会增多。事先静脉注射阿片受体阻断剂纳络酮（ｎａｌｏｘｏｎｅ，Ｎａｌ）均可以阻断这两种效应，但单独使用Ｎａｌ对脾交感神经兴奋性没有影响。随脾交感神经冲动数的增多和减少，血压亦有一定程度的升高和降低，但体温无明显变化。结论：Ｍｅｔ－Ｅｎｋ可以在中枢神经系统内通过阿片受体介导的通路调节脾交感神经的兴奋性。

AIM:To investigate the action of met-enkephalin(Met-Enk)injected into the third cerebral ventricle on splenic sympathetic nerve activity in this study.METHODS:Male Sprague-Dawley rats with urethane and α-chloralose anaesthesia were used.RESULTS:After microinjection of Met-Enk(1 μg and 100 μg respectively)into the third cerebral ventricle,we found that microinjection with 1 μg Met-Enk into the third cerebral ventricle produced a depress on the splenic sympathetic nerve filaments,while 100 μg Met-Enk produced an increase of the splenic sympathetic nerve filaments.This effect could be blocked by intravenous injection of opioid receptor antagonist naloxone(Nal),while Nal alone injected intravenously had no effect on the splenic nerve activity.The blood pressure changes with discharges of splenic nerve activity,while body temperature had no change.CONCLUSION:Met-Enk can modulate splenic sympathetic nerve activity through opioid receptors in the central nervous system.