门静脉高压症大鼠血管壁上血管紧张素Ⅱ受体的定量研究  

A quantitative study on vascular angiotensin Ⅱreceptors in rats with portal hypertension

作　　者：李继坤[1] 戴植本[2] 崔武任[2] 胡燕[2] 

机构地区：[1]上海市第一人民医院外科,200080 [2]同济医科大学,武汉430030

出　　处：《肝胆外科杂志》1997年第6期366-369,共4页Journal of Hepatobiliary Surgery

摘　　要：目的探讨门静脉高压症时机体血管对血管紧张素Ⅱ（A-Ⅱ）反应性下降的发生机理及其在门静脉高压症血流动力学变化中的作用。方法采用放射配基结合分析法检测肝前型门静脉高压症大限不同部位血管壁上A-Ⅱ受体的最大结合容量（Bmax）、平衡解高常数（Kd）变化。结果门静脉高压症组胸主动脉、肠系膜上动脉和门脉壁上A-Ⅱ受体的Bmax（分别为113．7±19．4fmol／mg蛋白、206．9±393fmol／mg蛋白和31．5±9．3fmol／mg蛋白）均按对照组（分别为1468±24．6fmol／mg蛋白、2972±44.7fmol／mg蛋白和534±12．1fmol／mg蛋白）明显降低（P＜0．01）；肠系膜上动脉的Kd值（1．03±0．11nM）较对照组（0．88±0．08nM）明显升高（P＞0．05），胸主动脉和门静脉的Kd植虽较对照组略有升高，但无统计学意义．结论门静脉高压症时机体血管对A-Ⅱ反应性下降的原因之一在于血管壁上A-Ⅱ受体的数量减少和亲和力下降，从而对高动力循环状态形成起着一定的介导作用。Objective To investigate the mechanism of the decreased vascular reactivity to angiotensin Ⅱ(A- Ⅱ) in portal hypertension and its significance in the hemodynamic changes. Methods A - Ⅱreceptor maximal binding capacity (Bmax) and dissociation constants (Kd) of different blood vessels in rats with prehepatic portal hypertensi0n were studied by radioligand binding analysis. Results The A- Ⅱreceptor Bmax in the thoracic aorta,superior mesenteric artery and portal vein of portal hypertensive animals (113. 7±19. 4fmol/mg protein, 206. 91±39. 3fmol/mg protein and 31. 5 ± 9. 2fmol/mg protein respectively) was all significantly lower than that of controls (146. 8±24. 5fmol/protein, 297. 2±44. 7fmol/mgprotein and 53. 4±12. 1fmol/mg protein respective1y,P<0. 01 ). The A- Ⅱ receptor Kd in the superior mesenteric artery was markedly increased in portal hypertensive animals (1. 03±0. 11nM)compared with that in controls (0. 88±0.08nM,P<0. 05) . In the thoracic aortaand portal vein,the A- Ⅱrecepor Kd in portal hypertensive animals was slightly higher than in controls,but no significant difference was observed between the two groups. ConcIusionThe vascular hyporedponsiveness to A- Ⅱin portal hypertension is caused partially by a reduction i number and a decrease in affinity of vascular A- Ⅱreceptors,and these changes may possibly lead to the formation of hyperdynamic circulation.

关 键 词：门脉高血压 血和壁 血管紧张素Ⅱ 受体 病理 

分 类 号：R657.340.2[医药卫生—外科学]