豚鼠交感神经节非胆碱能迟慢兴奋性突触后电位与蛙皮素、P物质的关系

The Relationship between Non-cholinergic, Late Slow-excitatory Postsynaptic Potential and Bombesin or Substance P in Sympathetic Ganglia of Guinea-pig

运用玻璃微电极细胞内记录技术 ,观察豚鼠 (Caviaporcellus)离体肠系膜下神经节 (IMG)细胞非胆碱能迟慢兴奋性突触后电位 (ls EPSP)与蛙皮素 (BOM)、P物质 (SP)的关系 ,以探讨肽类神经递质在外周神经系统中的作用。结果显示 ,SP去极化、BOM去极化与ls EPSP具有相关性 ;SP受体脱敏使SP敏感细胞的ls EPSP减弱或消失 ,但不影响BOM引起的去极化 ;BOM受体脱敏使BOM敏感细胞的ls EPSP减弱或消失 ,但不影响SP引起的去极化。大部分ls EPSP阳性细胞对SP、BOM敏感 ,而对SP、BOM均不敏感的细胞多数不出现ls EPSP。结果提示 ,BOM、SP通过IMG细胞膜上相应受体参与了ls EPSP的形成 ,受体间无交互脱敏现象。

In order to investigate the relationship between late slow-Excitatory Postsynaptic Potential(ls-EPSP) and Bombesin(BOM) or Substance P(SP) in sympathetic ganglia, intracellular recording technique was used on isolated inferior mesenteric ganglion(IMG) cells of Guinea-pig. The results showed that the SP-induced depolarization and BOM-induced depolarization were related to ls-EPSP. SP receptor desensitization abolished or markedly attenuated ls-EPSP in SP-sensitive neurons, but had no effect on BOM-mediated depolarization. By contrast, BOM receptor desensitization abolished or markedly attenuated ls-EPSP in BOM-sensitive neurons, while it had no effect on SP-mediated depolarization. The results demonstrate that BOM and SP can produce ls-EPSP via respective receptor on the membrane of IMG synapses and there is no cross desensitization between receptors.