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吗啡对于蟾蜍离体脊髓的兴奋作用

胡国渊

中国科学院上海药物研究所. 上海

摘要

在蟾蜍离体脊髓标本上,吗啡10~(-5)—10~(-3)M 能增大背根-腹根反射(DR-VRR),此增大作用不被纳洛酮拮抗,但10~(-4)M 的纳洛酮可轻度增大 DR-VRR。含菲核结构的阿片生物碱蒂巴因、可待因的兴奋作用强于吗啡,这三种药物在更高浓度时则抑制、甚至取消 DR-VRR。不含菲核结构的合成镇痛药美沙酮、哌替啶及脑啡肽类似物 FK33-824对 DR-VRR只起抑制作用。虽然吗啡能阻滞脊髓突触前抑制,并以可被纳洛酮逆转的方式取消刺激腹根诱发的背根电位(VR-DDRP),吗啡增大 DR-VRR 并非由于它的去抑制作用。该文结果提示,吗啡的兴奋作用与阿片受体无关,并为含菲核结构的阿片生物碱所特有。

关键词： 蟾蜍离体脊髓; 背根-腹根反射; 吗啡; 蒂巴因; 可待因

Excitatory effects of morphine on toad spinal cord in vitro

Hu Guoyuan

Shanghai Institute of Materia Medica, Academia Sinica. Shanghai, China

Abstract

The effects of morphine on the electrical reflex activities of toad spinal cord in vitro were studied. Morphine 10~(-5)-10~(-3) M enhanced the ventral root reflex response evoked by dorsal root stimulation (DR-VRR). The effect of morphine was not antagonized by naloxone which itself enhanced DR-VRR slightly at a concentration of 10~(-4) M. The phenanthrene ring containing opium alkaloids, codeine and thebaeine (a compound without opiate activity) exerted more potent excitatory effects than morphine. However, these 2 compounds as well as morphine depressed or abolished DR-VRR at still higher concentrations. Methadone, pethidine and FK33-824, an enkephain analogue, which do not contain a phenanthrene ring, did not enhance, but depress DR-VRR. Although morphine blocked spinal presynaptic inhibition, and abolished dorsal root potential evoked by ventral root stimulation (VR-DRP) that can be reversed by naloxone,the enhancement of DR-VRR.by morphine did not seem to be attributed to this disinhibitory effect. The results suggested that excitation of toad spinal cord by morphine was unrelated to opiate receptors but appeared to be characteristic of the alkaloids containing a phenanthrene ring.

Key words: Toad spinal cord in vitro;Ventral root reflex;Response evoked by dorsal root stimulation;Morphine;Codeine

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引用本文：

胡国渊. 吗啡对于蟾蜍离体脊髓的兴奋作用[J]. 生理学报 1985; 37 (3): .

Hu Guoyuan. Excitatory effects of morphine on toad spinal cord in vitro. Acta Physiol Sin 1985; 37 (3): (in Chinese with English abstract).