【摘要】 以辐射热照射家兔鼻嘴部皮肤,测定甩头反应潜伏期(ERL)作为痛阈。通过预先埋植的慢性套管向中脑导水管周围灰质(PAG)注射甲七肽降解酶抑制剂 Captopril,观察其镇痛作用以及加强电针镇痛的作用能否被特异的甲七肽抗血清所对抗。(1)单侧 PAG 注射 Captopril240 nmol 的镇痛作用可为同一部位注射甲七肽抗血清(1μl)所翻转,注入甲啡肽抗血清则无效。(2)单侧 PAG 注射 Captopril 60 nmol 有加强电针镇痛的作用。该作用可被1μl 甲七肽抗血清所完全取消,将抗血清量减少到0.1μl 则无效。以上结果说明 PAG 内的甲七肽样免疫活性物质在镇痛和电针镇痛中发挥重要作用。更多还原

【Abstract】 The present study was performed to evaluate the possible analgesic effect ofa newly found C-terminal extended Met-enkephalin(Met-enkephalin-Arg~6-Phe~7,MEAP)in periaqueductal gray(PAG)of the rabbit.Nociception was assessedby measuring the latency of the escape response(ERL)elicited by radiant heatfocused on the snout of the rabbit.Captopril,the specific inhibitor of the MEAP degrading enzyme,when in-jected into PAG through chronically implanted intracranial cannula at a dose of240 nmol,produced marked analgesia which could be antagonized by MEAPantiserum(1μl)injected into the same site.Antiserum directed to Met-enkeph-alin(ME)was not effective at this extent.Microinjection of captopril into PAG at a dose of 60 nmol caused marked poten-tiation of the effect of electroacupuncture(EA)analgesia.This potentiating effectwas completely eliminated by microinjection of 1μl of MEAP antiserum into PAG,being ineffective at a dose of 0.1 μl.These findings suggest that the MEAP-like immunoreacfive substance in PAG ofthe rabbit may have an analgesic effect and may play an important,role in mediatingEA analgesia.更多还原