Cardell L O, Uddman R, Luts A, Sundler F
Department of Otorhinolaryngology, Malmö General Hospital, Sweden.
Regul Pept. 1991 Nov 26;36(3):379-90. doi: 10.1016/0167-0115(91)90071-n.
The lower airways of guinea-pigs were analyzed for pituitary adenylate cyclase activating peptide (PACAP) using immunocytochemistry. In the trachea a moderate supply of PACAP-immunoreactive nerve fibers occurred around smooth muscle bundles, glands and small blood vessels. In the lung, PACAP-immunoreactive nerve fibers were distributed around small glands and bronchi. A rich supply of PACAP immunoreactive nerve fibers was found around blood vessels in the lungs. PACAP-suppressed smooth muscle responses were analysed using isolated circular segments of trachea, pulmonary arteries and aorta of guinea-pigs. In both airways and arteries PACAP caused a concentration-dependent relaxation of precontracted segments. The maximal relaxation effects were more pronounced in the airways than in the arteries while the order of potency was aorta greater than pulmonary artery greater than trachea. The effect of PACAP was compared to those of acetylcholine (ACh) and vasoactive intestinal peptide (VIP). In the pulmonary artery the vasomotor responses expressed as maximal dilatation had the order: ACh greater than VIP = PACAP while the order of potency was PACAP = VIP greater than ACh. In the trachea, PACAP was slightly more potent than VIP. The relaxatory responses to PACAP in the trachea and the intrapulmonary arteries were unaffected by pretreatment with atropine, prazosin, yohimbine, propranolol, mepyramine, cimetidine and Spantide. Removal of the endothelium abolished PACAP-induced vascular relaxation. Conceivably, PACAP-containing nerve fibers play a role in the regulation of airway resistance and local blood flow.
运用免疫细胞化学方法对豚鼠的下呼吸道进行垂体腺苷酸环化酶激活肽（PACAP）分析。在气管中，PACAP免疫反应性神经纤维适度分布于平滑肌束、腺体和小血管周围。在肺中，PACAP免疫反应性神经纤维分布于小腺体和支气管周围。在肺内血管周围发现有丰富的PACAP免疫反应性神经纤维。利用豚鼠气管、肺动脉和主动脉的离体环形节段分析了PACAP对平滑肌反应的抑制作用。在气道和动脉中，PACAP均可使预收缩节段出现浓度依赖性舒张。气道中的最大舒张效应比动脉中更明显，而效力顺序为主动脉＞肺动脉＞气管。将PACAP的作用与乙酰胆碱（ACh）和血管活性肠肽（VIP）的作用进行了比较。在肺动脉中，以最大扩张表示的血管运动反应顺序为：ACh＞VIP = PACAP，而效力顺序为PACAP = VIP＞ACh。在气管中，PACAP的效力略强于VIP。气管和肺内动脉对PACAP的舒张反应不受阿托品、哌唑嗪、育亨宾、普萘洛尔、美吡拉敏、西咪替丁和Spantide预处理的影响。去除内皮可消除PACAP诱导的血管舒张。可以想象，含PACAP的神经纤维在气道阻力和局部血流的调节中发挥作用。
