中脑导水管周围灰质在侧脑室注入微量吗啡或纳洛酮所引起的镇痛或拮抗镇痛中的作用

本工作进一步探索中脑导水管周围灰质(PAG)在吗啡镇痛与纳洛酮拮抗吗啡镇痛中的作用。实验在清醒受限制的大鼠上进行,以电刺激鼠尾出现的甩尾和嘶叫为痛反应指标。结果表明:(1)侧脑室注射微量纳洛酮后,可使电刺激 PAG 或注射微量吗啡于 PAG 所引起的镇痛效应受到明显拮抗;(2)损毀 PAG 或注射微量纳洛酮于 PAG 后,可使由侧脑室注入微量吗啡所引起的镇痛效应显著减弱。由此可见 PAG 既是侧脑室注射吗啡镇痛作用的重要中枢部位,又是侧脑室注射纳洛酮拮抗吗啡镇痛的重要中枢部位。

THE ROLE OF PERIAQUEDUCTAL GRAY(PAG)IN ANALGESIA OR ANTI-ANALGESIA INDUCED BY INTRAVENTRICULAR INJECTION OF MORPHINE OR NALOXONE

The purpose of this study was to observe the role of PAG in analgesia or anti-analgesia induced by microinjection of morphine or naloxone into the lateral ven-tricle.Experiments were performed on waking and restrained albino rats.Tail-flick and vocalization in response to electrical stimulation of the tail were taken asindices of pain response.The following results were observed.(1)The effect of analgesia produced by electrical stimulation of the PAG ormicroinjection of morphine into the PAG was significantly reduced after a mi-crodose of naloxone was administrated into the lateral ventricle.(2)The effect of analgesia induced by microinjection of morphine into thelateral ventricle was reduced significantly after PAG was electrolytically destroyedor a microdose of naloxone was administrated into it.These results show that PAG is an important site not only for the analgesicaction of morphine but also for the antagonistic analgesic effect of naloxone.