ALTERATION IN CONTRACTILE RESPONSE TO NORADRENALINE, 5-HYDROXYTRYPTAMINE, S ARAFOTOXIN 6c, AND ANGIOTENSINⅡ IN RAT MESENTERIC ARTERY DURING ORGAN CULTURE

摘要

Objective To compare the vasoconstrictive eff ects of 9 mediators on fresh and incubated mesenteric arteries of rats. Methods The superior mesenteric artery of rat was removed and t he endothelium was denuded. The vessels were cut into 1 mm long cylindrical segm ents and subjected to organ culture for 24 hours. Fresh or incubated segments we re immersed into tissue baths and the concentration-response curves were obtain ed by cumulative administration of the vasoconstrictors. Results In fresh mesenteric artery, endothelin-1 (ET-1), 5-h ydroxytryptamine (5-HT), noradrenaline (NA), 5-carboxamidotryptamine (5-CT), and angiotensinⅡ (AngⅡ) induced potent and sustained constrictions in a concen tration-dependent manner. The contraction induced by sarafotoxin 6c (S6c) was w eak, while bradykinin (BK), des-Arg-bradykinin (DA-BK), and human urotensinⅡ (hUT-II) showed no detectable contraction. The concentraion-response curves i n order of slopes was ET-1, NA, 5-HT, 5-CT, and AngⅡ. The order of the maxim um contractions was ET-1>NA=5-HT=5-CT>AngⅡ>S6c. After organ culture, the con centration-response curves induced by S6c, NA, and 5-HT were significantly inc reased, while that induced by AngⅡ was decreased as comparing to fresh arteries . BK contracted the artery only weakly. Conclusion Organ culture changed the phenotypes towards an increased efficacy of NA, 5-HT, S6c, and a reduced efficacy of AngⅡ, which is in accordance with the results o f pharmacological characterization in some human vascular disease.