Dunn W R, Gardiner S M
Department of Physiology and Pharmacology, Queen's Medical Centre, Medical School, University of Nottingham, UK.
Hypertension. 1995 Sep;26(3):390-6. doi: 10.1161/01.hyp.26.3.390.
In this study we examined the structural and functional properties of mesenteric resistance arteries isolated from normotensive and hypertensive vasopressin-deficient rats. Hypertensive rats had a significantly higher mean arterial pressure (176 +/- 3 mm Hg) than normotensive controls (121 +/- 2 mm Hg). First- and second-order mesenteric resistance arteries were set up in a pressure myograph and pressurized to the mean arterial pressure of the rat from which they had been isolated. Vessels were fixed with glutaraldehyde, embedded in Araldite, sectioned, and examined histologically. First- and second-order mesenteric resistance arteries from hypertensive rats displayed a reduced internal diameter and increased media-to-lumen ratio compared with their normotensive controls. However, there was no evidence for an increased media content, indicating that the reduced internal diameter of hypertensive arteries was consequent to either remodeling of similar amounts of wall material or a reduced artery distensibility but not vascular growth. Pressurized arteries were also examined with respect to their responsiveness to the vasoconstrictors norepinephrine and arginine vasopressin and to the endothelium-dependent vasodilator acetylcholine and the endothelium-independent vasodilator papaverine. Both first- and second-order mesenteric arteries from hypertensive rats displayed enhanced sensitivity to norepinephrine compared with their normotensive controls. This effect was specific for norepinephrine, because responses to arginine vasopressin were similar in vessels isolated from normotensive and hypertensive rats. No evidence was found for an impaired endothelium-dependent vasodilatation in arteries from hypertensive rats. Indeed, in hypertensive vasopressin-deficient rats responses to acetylcholine were increased in first-order arteries compared with those from normotensive rats. Responses to papaverine were similar in arteries isolated from either normotensive or hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)
在本研究中，我们检测了从正常血压和高血压血管升压素缺乏大鼠分离出的肠系膜阻力动脉的结构和功能特性。高血压大鼠的平均动脉压（176±3 mmHg）显著高于正常血压对照组（121±2 mmHg）。将一级和二级肠系膜阻力动脉置于压力肌动描记仪中，并将压力升至分离出这些动脉的大鼠的平均动脉压。血管用戊二醛固定，包埋在环氧树脂中，切片并进行组织学检查。与正常血压对照组相比，高血压大鼠的一级和二级肠系膜阻力动脉内径减小，中膜与管腔比值增加。然而，没有证据表明中膜含量增加，这表明高血压动脉内径减小是由于等量壁材料的重塑或动脉扩张性降低，而非血管生长所致。还检测了加压动脉对血管收缩剂去甲肾上腺素和精氨酸血管升压素、内皮依赖性血管舒张剂乙酰胆碱以及内皮非依赖性血管舒张剂罂粟碱的反应性。与正常血压对照组相比，高血压大鼠的一级和二级肠系膜动脉对去甲肾上腺素的敏感性均增强。这种效应是去甲肾上腺素特有的，因为从正常血压和高血压大鼠分离出的血管对精氨酸血管升压素的反应相似。未发现高血压大鼠动脉的内皮依赖性血管舒张功能受损。事实上，在高血压血管升压素缺乏大鼠中，一级动脉对乙酰胆碱的反应比正常血压大鼠增强。从正常血压或高血压大鼠分离出的动脉对罂粟碱的反应相似。（摘要截断于250字）
