MICROVASCULAR ALTERATIONS IN HYPERTENSION

微血管在发育过程中会发生形态变化。 高血压。小动脉壁增厚与实际病变 据报道，高血压动物的某些血管数量和 人类。对体液制剂的敏感度也可能增加。这个 这些变化对毛细血管流体交换的影响，调节 血液流动与高血压的发展和维持 开始被探索。我们建议使用直接微循环 股薄肌和肠系膜血管床的技术，包括： 活体血管荧光显微镜定量体视学研究 船用电视显微镜的长度和表面积密度 直径、壁腔比、双狭缝红细胞速度 光度学方法、伺服零位微压及其应用 血管活性物质与微吸管，以研究微循环 几种大鼠模型高血压形成过程中的动态变化。 将对SHR的微血管变化进行纵向研究， 1-肾-1夹、1-肾-1夹、DOCA-盐和Dahl高血压大鼠。 确定神经、局部/体液的相对影响 机械，测量将在3个连续的状态下进行， 失去神经，血管扩张。5个型号的比较将牵涉到 负责结构变化的机制以及决定 结构变化是否特定于某一类型的 高血压，或共同分享。微血管压力分布与红色 细胞速度数据将添加要关联的生理信息 观察到形态改变。各种降压药将 长期而尖锐地用来确定导致 微血管改变。对去甲肾上腺素、血管紧张素II的敏感性 和加压素将通过直接应用于 带有微吸管的微血管。的功能意义 将通过研究运动来研究微血管的变化 脑微血管充血、反应性充血和肌源性反应 这些高血压模型。这些研究将为以下工作提供信息 评估微循环中的结构变化并确定 它们在高血压中的原因、作用和功能意义。

Morphological changes occur in microvessels during development of hypertension. Thickening of arteriolar walls and alterations in actual number of certain vessels have been reported in hypertensive animals and humans. Sensitivity to humoral agents also may be increased. The implication of these changes for capillary fluid exchange, regulation of blood flow, and development and maintenance of hypertension are just beginning to be explored. We propose to use direct microcirculatory techniques on gracilis muscle and mesenteric vascular beds, including: in vivo quantitative stereology using intravital fluoromicroscopy for vessel length and surface area densities, television microscopy for vessel diameters and wall/lumen ratios, red cell velocity by the dual-slit photometric method, servo-null micropressures, and application of vasoactive agents with micropipettes, to investigate microcirculatory dynamics during development of hypertension in several rat models. Longitudinal studies of the microvascular alterations will be made in SHR, 1-kidney-1-clip, 1-kidney-1-clip, DOCA-salt, and Dahl hypertensive rats. To determine the relative influence of neural, and local/humoral mechanisms, measurements will be made in 3 consecutive states, innervated, denervated, and vasodilated. Comparison of the 5 models will implicate mechanisms responsible for the structural changes as well as determine whether structural alterations are specific to a certain type of hypertension, or commonly shared. Microvascular pressure profiles and red cell velocity data will add physiological information to correlate with observed morphological alterations. Various antihypertensive agents will be used chronically and acutely to determine the mechanisms leading to the microvascular alterations. Sensitivity to norepinephrine, angiotensinII and vasopressin will be determined by direct application to the microvessels with micropipettes. The functional significance of microvascular alterations will be investigated by studying exercise hyperemia, reactive hyperemia, and myogenic responses of microvessels in these hypertensive models. These studies will provide information to assess structural alterations in the microcirculation and to determine their cause, role, and functional significance in hypertension.