Yen M H, Sheu Y Z, Chiou W F, Wu C C
Department of Pharmacology, National Defense Medical Center, Taipei, Taiwan, R.O.C.
Eur J Pharmacol. 1990 May 16;180(2-3):209-16. doi: 10.1016/0014-2999(90)90304-o.
The contraction of ring segments of canine mesenteric and basilar arteries in response to angiotensins II and III was investigated. Removal of the mesenteric endothelium resulted in markedly intensified contraction in response to angiotensin II but did not affect the contractile response to angiotensin III. This angiotensin II-induced contraction was augmented by indomethacin (10(-5) M) and by methylene blue (5 X 10(-6) M) in the intact rings. These findings suggest that mesenteric endothelium modulates the vasoconstriction induced by angiotensin II but not that induced by angiotensin III. They also indicate that the mesenteric endothelium may contain relaxing factors such as prostacyclin or endothelium-derived relaxing factor as mediators. In contrast with mesenteric endothelium, removal of the basilar endothelium produced a much reduced contraction in response to either angiotensin. Acetylcholine, which caused a dose-dependent contraction in the basilar artery, elicited only a low-grade response if the functional endothelium was absent. These results suggest that basilar endothelium may release a contracting factor. It is possible that the main modulator of the peripheral arteries is a relaxing factor but that of the cerebral arteries is a contracting factor.
研究了犬肠系膜动脉和基底动脉环段对血管紧张素II和III的收缩反应。去除肠系膜内皮会导致对血管紧张素II的收缩反应明显增强，但不影响对血管紧张素III的收缩反应。在完整的血管环中，吲哚美辛（10^(-5)M）和亚甲蓝（5×10^(-6)M）可增强这种由血管紧张素II诱导的收缩。这些发现表明，肠系膜内皮可调节血管紧张素II诱导的血管收缩，但不调节血管紧张素III诱导的血管收缩。它们还表明，肠系膜内皮可能含有诸如前列环素或内皮源性舒张因子等舒张因子作为介质。与肠系膜内皮相反，去除基底动脉内皮后，对任何一种血管紧张素的收缩反应都大大降低。乙酰胆碱在基底动脉中引起剂量依赖性收缩，但如果功能性内皮不存在，则只会引起低度反应。这些结果表明，基底动脉内皮可能释放一种收缩因子。外周动脉的主要调节因子可能是舒张因子，而脑动脉的主要调节因子可能是收缩因子。
