Zheng X F, Zhao M H, Lin B, Mao L G, Bian R L
Department of Pharmacology, Zhejiang Medical University, Hangzhou, China.
Zhongguo Yao Li Xue Bao. 1990 Mar;11(2):133-7.
Relaxing responses of strips of rabbit pulmonary artery (RPA) with endothelium (+E) to norepinephrine (NE) during sustained contraction with KCl 20 mmol/L in the presence of propranolol (Pro) 10 mumol/L and prazosin (Pra) 1 mumol/L were more sensitive than those without endothelium (-E) to NE. These responses were inhibited by yohimbine (Yoh) 1 mumol/L. However, the relaxing responses of the strips to clonidine (Clo) were not different between RPA strips +E and -E in the presence of Pro+ Pra or Pro + Pra + Yoh 1 mumol/L. Relaxing responses of RPA strips -E precontracted by phenylephrine (PE) 1 mumol/L to Pra and Clo were greater than that of those precontracted by KCl 20 mmol/L. The relaxing responses of these strips precontracted by PE to Pra were larger than those precontracted by PE mumol/L; but that of those precontracted by PE and Clo to Yoh were not different. The results suggest that integrity of the endothelium is an important factor in the relaxing responses of RPA strips to NE. The relaxing effect of Clo on RPA strips precontracted by KCl 20 mmol/L may be due to alpha 1-adrenoceptor blockade on smooth muscle cells of the RPA strips.
在10 μmol/L普萘洛尔（Pro）和1 μmol/L哌唑嗪（Pra）存在的情况下，用20 mmol/L氯化钾使兔肺动脉（RPA）条带持续收缩时，有内皮（+E）的RPA条带对去甲肾上腺素（NE）的舒张反应比无内皮（-E）的条带对NE的反应更敏感。这些反应被1 μmol/L育亨宾（Yoh）抑制。然而，在Pro + Pra或Pro + Pra + 1 μmol/L Yoh存在的情况下，RPA条带+E和-E对可乐定（Clo）的舒张反应没有差异。1 μmol/L去氧肾上腺素（PE）预收缩的RPA条带-E对Pra和Clo的舒张反应大于20 mmol/L氯化钾预收缩的条带。PE预收缩的这些条带对Pra的舒张反应大于PE μmol/L预收缩的条带；但PE和Clo预收缩的条带对Yoh的舒张反应没有差异。结果表明，内皮的完整性是RPA条带对NE舒张反应的一个重要因素。Clo对20 mmol/L氯化钾预收缩的RPA条带的舒张作用可能是由于对RPA条带平滑肌细胞的α1 - 肾上腺素能受体阻滞。
