目的 :探讨不同种属动物、不同区域血管内皮细胞乙酰胆碱激活蛋白 (endothelialproteinacetivatedbyacetylcholine ,EPA)介导内皮依赖性舒血管效应的特性及其在高血脂诱发动脉粥样硬化形成过程中的变化特征。方法 :采用离体血管条实验方法 ,以去甲肾上腺素预收缩血管 ,观察乙酰胆碱 (ACh)诱导正常和高血脂动物血管舒张反应 ,并计算EC50 。结果 :在兔主动脉、颈动脉、股动脉、肺动脉、肾动脉 ,猫主动脉、股动脉、肾动脉、肠系膜动脉、冠状动脉 ,ACh均诱导内皮依赖性血管舒张反应 ,但EC50 值不同。兔血管中 ,EPA对于ACh敏感性的顺序依次为肺动脉 >肾动脉 >主动脉 >股动脉 >颈动脉。在猫血管中其顺序为冠状动脉 >主动脉 >股动脉 >肠系膜动脉 >肾动脉。在高血脂诱发动脉粥样硬化兔主动脉、颈动脉及肺动脉上 ,ACh诱导的舒张反应明显降低 ,但在肾动脉和股动脉上无显著变化。结论 :EPA介导的内皮依赖性血管舒张反应广泛存在于猫、兔不同组织的动脉血管上 ,但不同种属动物、不同区域组织血管EPA对于ACh的敏感性不同。在高血脂诱发兔动脉粥样硬化的实验模型上 ,EPA功能降低 OBJECTIVE: To investigate the characteristics of endothelium-dependent vasodilator effect mediated by acetylcholinesterase (EPA) in different kinds of animals and different regions and their changes in the pathogenesis of atherosclerosis induced by hyperlipidemia. Methods: Using ex vivo vascular strips, norepinephrine precontracted blood vessels to observe acetylcholine (ACh) induced vasodilatory response in normal and hyperlipidemic animals, and calculate EC50. Results: Endothelium-dependent vasorelaxation was induced in rabbit aorta, carotid artery, femoral artery, pulmonary artery, renal artery, feline aorta, femoral artery, renal artery, mesenteric artery, coronary artery and ACh. In rabbit blood vessels, the order of sensitivity of EPA to ACh was pulmonary artery> renal artery> aorta> femoral artery> carotid artery. In cat vessels, the order is coronary artery> aorta> femoral artery> mesenteric artery> renal artery. ACh-induced diastolic response was significantly decreased in the aorta, carotid and pulmonary arteries of atherosclerotic rabbits induced by hyperlipidemia, but no significant changes were found in the renal and femoral arteries. CONCLUSION: EPA-mediated endothelium-dependent vasodilation is widely observed in arterial vessels of different tissues of cats and rabbits. However, the sensitivity of EPA to ACh in different species of animals and in different regional tissues is different. The EPA function is reduced in hypercholesterolemic experimental models of atherosclerosis in rabbits