【摘要】 本文报道中枢去甲肾上腺素（NE）能下行系统的脊髓末梢以及脊髓内的α受体在吗啡镇痛机制中的作用。结果显示,皮下注射6mg/kg 吗啡可使脊髓中的 NE 代谢终产物3-甲氧基4-羟基苯乙二醇硫酸盐（MHPG·SO₄）含量升高,提示脊髓 NE 的更新加速;反复多次注射吗啡引起吗啡镇痛耐受的动物,该反应消失。脊髓蛛网膜下腔注射α受体阻断剂酚妥拉明可部分对抗全身注射小剂量吗啡的镇痛作用,选择性的α₁受体阻断剂哌唑嗪或α₂受体阻断剂育亨宾有类似作用。阻断脊髓α₁或α₂受体对脊髓蛛网膜下腔直接注射微量吗啡的镇痛作用无显著影响,以上结果表明,下行 NE 能系统在吗啡镇痛机制中具有重要作用。更多还原

【Abstract】 The present study was performed in an attempt to define the involvement ofdescending noradrenergic pathway and the spinal α-adrenoceptors in the mechanismsof morphine analgesia.It was found that acute morphine treatment（6mg/kg,sc）increased the spinal content of 3-methoxy-4-hydroxyphenylglycol sulfate（MHPG·SO₄）,a metabolic end-product of central norepinephrine（NE）,thus suggesting anincreased NE turn-over.This response was no longer present in animals made to-lerant to morphine analgesia by chronic morphine treatment.Different kinds ofα-adrenoceptor antagonists were injected intrathecally to assess their effects on mor-phine analgesia.While analgesia produced by a small dose of systemic morphinewas attenuated by phentolamine,as well as by selective α₁ or α₂-blocker,prazosinor yohimbine,analgesia induced by intrathecal morphine was not affected by prazo-sin or yohimbine.These findings indicate that descending noradrenergic systemfrom supaspinal structures may serve as one of the important mechanisms formorpine analgesia.更多还原