【摘要】 本文以微量的α受体激动剂氯压啶或α受体拮抗剂酚妥拉明经慢性埋藏套管注入家兔脑内四个核团:伏核、杏仁核、缰核和导水管周围灰质(PAG),观察其对指压穴位镇痛作用的影响。氯压啶注入双侧缰核、伏核和PAG可显著对抗指压镇痛,酚妥拉明注入缰核则有显著加强作用。将同量药物注入以上三核团的周围区域或杏仁核内均无效。实验结果说明中枢儿茶酚胺可通过α受体对抗指压镇痛,这种效应具有明显的部位特异性:缰核在该效应中占有极重要的位置,PAG和伏核可能也起重要作用.更多还原

【Abstract】 Experiments were performed on 91 rabbits to assess whether the effect of acupuncture analgesia (AA) could be modified by the activation or blockade of the α-receptors in discrete brain areas. Minute amount of α-agonist clonidine (3.5μg/5μl) or α-antagonist phentolamine (10μg/5μl) was injected into each brain area through chronically implanted cannula within 20 minutes. Finger pressing of the Kuenlun point which was proved to be of the same effectiveness as manual needling was given during the last 10 minutes of intracerebral injection.The latency of the head-withdrawal reaction induced by radiant heat exposure was taken as the nociceptive index. The effect of intracerebral injection on AA was correlated with the site of injection as varified on brain slices at the end of the experiment. The main results were as follows:The effect of AA was found to be significantly attenuated by the injection of α-agonist clonidine into bilateral habenula, nuclei accumbens and periaquaductal grey and significantly augmented by the injection of α-antagonist phentolamine into bilateral habenula. No significant effect on AA was noticed when the same drugs were injected into bilateral amygdala. Nor was there any significant effect on AA when the cannula was directed outside the above mentioned nuclei or into the third ventricle.It is concluded that activation of the α-receptors in habenula, and perhaps in nucleus accumbens and periaquaductal grey as well, seems to exert a powerful antagonistic influence on the effectiveness of AA in the rabbit. The possible mechanisms of this antagonistic action were discussed.更多还原