Dray A, Hankins M W, Yeats J C
Sandoz Institute for Medical Research, London, U.K.
Neuroscience. 1989;31(2):479-83. doi: 10.1016/0306-4522(89)90390-4.
Substance P-like immunoreactivity was assayed in superfusates of guinea-pig ureters following stimulation of afferent fibres with capsaicin, potassium chloride and the calcium channel agonist Bay K 8644. Capsaicin-evoked release of substance P-like immunoreactivity was calcium-dependent but unaffected by cobalt. Under appropriate conditions release was dose-related (ED50 = 610 nM) and reproducible. Selective desensitization to capsaicin could be demonstrated following prolonged exposure to different doses of capsaicin. No desensitization to capsaicin was observed following afferent fibre stimulation with a combination of Bay K 8644 and K+, which released a similar amount of substance P-like immunoreactivity as a desensitizing capsaicin stimulus. These data suggest that depletion of releasable substance P-like reactivity is unlikely to account for selective desensitization of ureteric primary afferent fibres to capsaicin.
在用辣椒素、氯化钾和钙通道激动剂Bay K 8644刺激传入纤维后，对豚鼠输尿管的灌流液进行了P物质样免疫反应性检测。辣椒素诱发的P物质样免疫反应性释放依赖于钙，但不受钴的影响。在适当条件下，释放呈剂量相关（半数有效剂量=610 nM）且可重复。长时间暴露于不同剂量的辣椒素后，可证明对辣椒素的选择性脱敏。在用Bay K 8644和钾离子联合刺激传入纤维后，未观察到对辣椒素的脱敏现象，这种联合刺激释放的P物质样免疫反应性与脱敏剂量的辣椒素刺激释放的量相似。这些数据表明，可释放的P物质样反应性的耗竭不太可能是输尿管初级传入纤维对辣椒素选择性脱敏的原因。
