Elkouri S, Demers P, Couturier A, Cartier R
Service de Chirurgie, Institut de Cardiologie de Montréal, Québec, Canada.
Ann Chir. 1998;52(8):807-12.
Human infrarenal aorta is prone to develop atherosclerotic lesions. Infrarenal aortic blood flow depends on lower limb muscular activity. Blood flow variations cause shear stress variations known to influence endothelial reactivity. The purpose of this study is to compare vascular reactivity of the suprarenal and infrarenal aorta.
Endothelium-dependent relaxation to acetylcholine (ACH) and calcium ionophore (Cal), and endothelium-independent relaxation to sodium nitroprussiate (SNP) in 3 aortic segments (thoracic, abdominal suprarenal and infrarenal) harvested from Sprague-Dawley rats (n = 12) were studied in organ chambers.
Endothelium-dependent relaxations to ACH were similar for the 3 aortic segments. However, infrarenal aorta endothelial response to Cal was decreased compared to other segments whereas response to SNP was enhanced. Contractility to vasoconstrictor agonist (phenylephrine and KCl) was diminished compared to the suprarenal segments.
Endothelial reactivity is not homogeneous throughout the rat aorta. Endothelial reactivity to Cal seems decreased in the infrarenal aorta which suggests a diminished nitric oxide synthase activity. The increased sensitivity of the infrarenal aorta to nitric oxide donor such as SNP suggests a compensatory mechanism.
人体肾下腹主动脉易于发生动脉粥样硬化病变。肾下腹主动脉血流依赖于下肢肌肉活动。血流变化会导致已知会影响内皮反应性的剪切应力变化。本研究的目的是比较肾上腹主动脉和肾下腹主动脉的血管反应性。
在器官浴槽中研究从Sprague-Dawley大鼠（n = 12）获取的3个主动脉节段（胸段、腹段肾上和肾下）对乙酰胆碱（ACH）和钙离子载体（Cal）的内皮依赖性舒张，以及对硝普钠（SNP）的非内皮依赖性舒张。
3个主动脉节段对ACH的内皮依赖性舒张相似。然而，与其他节段相比，肾下腹主动脉对Cal的内皮反应降低，而对SNP的反应增强。与肾上节段相比，对血管收缩剂激动剂（去氧肾上腺素和氯化钾）的收缩性减弱。
大鼠主动脉内皮反应性并非均匀一致。肾下腹主动脉对Cal的内皮反应似乎降低，这表明一氧化氮合酶活性减弱。肾下腹主动脉对一氧化氮供体如SNP的敏感性增加表明存在一种代偿机制。
