Maggi C A, Theodorsson E, Santicioli P, Patacchini R, Barbanti G, Turini D, Renzi D, Giachetti A
Department of Pharmacology, A. Menarini Pharmaceuticals, Florence, Italy.
Neuroscience. 1990;39(3):833-41. doi: 10.1016/0306-4522(90)90266-7.
The aim of this study was to obtain indirect evidence of the presence of capsaicin-sensitive afferents in the human colon by studying the motor response to capsaicin of longitudinal strips from the human isolated taenia coli in parallel to the ability of capsaicin or KCl to induce peptide release from the human superfused colon. Capsaicin (1 microM) evoked a relaxation of the taenia, approaching 60-80% of the response to isoprenaline. Tachykinins evoked contractions of the taenia, while calcitonin gene-related peptide induced a relaxation. Neither tachyphylaxis to calcitonin gene-related peptide nor preincubation with an anti-calcitonin gene-related peptide serum did block the response to capsaicin which was also unaffected by tetrodotoxin, apamin, naloxone or an anti-galanin serum. Vasoactive intestinal polypeptide produced a concentration-dependent tetrodotoxin-resistant relaxation which was shifted rightward in the presence of anti-vasoactive intestinal polypeptide serum. The anti-vasoactive intestinal polypeptide serum reduced the response to capsaicin and application of capsaicin prevented the ability of anti-vasoactive intestinal polypeptide serum to block exogenous vasoactive intestinal polypeptide. Capsaicin (1 microM) evoked a significant release of vasoactive intestinal polypeptide-like immunoreactivity from the superfused muscle but not mucosa of the human colon. A significant vasoactive intestinal polypeptide-like immunoreactivity release was also observed in response to KCl (80 mM). KCl but not capsaicin evoked a significant release of neurokinin A-like immunoreactivity from colonic muscle and mucosa. No significant release of either substance P-, neuropeptide Y-, galanin- or calcitonin gene-related peptide-like immunoreactivity was detected in response to capsaicin or KCl although detectable levels of each peptide were evident in tissue extracts.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是通过研究人离体结肠带纵行肌条对辣椒素的运动反应，以及辣椒素或氯化钾诱导人离体结肠释放肽的能力，来获得人结肠中存在辣椒素敏感传入神经的间接证据。辣椒素（1微摩尔）引起结肠带松弛，接近对异丙肾上腺素反应的60 - 80%。速激肽引起结肠带收缩，而降钙素基因相关肽诱导松弛。对降钙素基因相关肽既无快速耐受现象，用抗降钙素基因相关肽血清预孵育也不阻断对辣椒素的反应，该反应也不受河豚毒素、蜂毒明肽、纳洛酮或抗甘丙肽血清的影响。血管活性肠肽产生浓度依赖性的河豚毒素抵抗性松弛，在抗血管活性肠肽血清存在时向右移位。抗血管活性肠肽血清降低了对辣椒素的反应，而应用辣椒素可防止抗血管活性肠肽血清阻断外源性血管活性肠肽的作用。辣椒素（1微摩尔）引起人结肠灌流肌肉而非黏膜中血管活性肠肽样免疫反应性的显著释放。对氯化钾（80毫摩尔）也观察到显著的血管活性肠肽样免疫反应性释放。氯化钾而非辣椒素引起结肠肌肉和黏膜中神经激肽A样免疫反应性的显著释放。尽管在组织提取物中每种肽的可检测水平明显，但对辣椒素或氯化钾均未检测到P物质、神经肽Y、甘丙肽或降钙素基因相关肽样免疫反应性的显著释放。（摘要截短于250字）
