VENULAR-ARTERIOLAR COMMUNICATION IN THE MICROCIRCULATION

流向外周循环的血液被设计成协调 根据组织的需求输送营养物质。任何增加 需要发生的血流是微动脉增加的结果。 直径。这种小动脉扩张可能是由一种或多种因素引起的 血管活性代谢物从组织中释放出来。这一机制通过它 小动脉接收来自组织的血管扩张信号尚不清楚。 本提案中描述的研究旨在确定 小静脉和小动脉之间的交通方式如下 调节小动脉直径。 具体假设涉及以下问题和衡量标准： 1)血管活性代谢物能否从小静脉扩散到 小动脉的浓度是否足以影响小动脉的直径？这 将通过测定微动脉的定性和定量来进行检测 不同直径的相邻小静脉灌注过程中的直径反应 血管活性代谢物。更多的研究将检查是否 物质从小静脉到小动脉的扩散发生在 组织的生理状态的变化。 2)如果有足够的代谢物从小静脉扩散到 穿过小动脉，由此产生的小动脉扩张是局部性的还是 扩张向上游传播，导致血液中更多的增加。 心流？这种膨胀可能是由于速度诱导机制造成的。 3)是否存在内皮细胞衍生因子的速度依赖性释放 会影响附近小动脉直径的小静脉？这 信息将通过证明小静脉的存在而确定 速度诱导小动脉血管扩张，然后阻断血管扩张 通过使用可用的EDRF阻滞剂。 每项研究的一个重要方面将是确定 这些机制中的每一种在微动脉调节中的生理作用 直径。

The blood flow to the peripheral circulation is designed to coordinate the delivery of nutrients with the demands of the tissue. Any increase in blood flow that need occur is the result of an increase in arteriolar diameter. This arteriolar dilation may be die to the effect of one or more vasoactive metabolites released from the tissue. The mechanism by which the arterioles receive the vasodilatory signal from the tissue is not know. The studies described in this proposal are designed to determine whether there is communication between venules and arterioles in such a manner as to regulate arteriolar diameter. Specific hypotheses involve the following questions and measurements: 1) Can there be a diffusion of vasoactive metabolites form a venule to an arteriole in sufficient concentration to affect arteriolar diameter? This will be tested by determining the qualitative and quantitative arteriolar diameter responses during perfusion of an adjacent venule with various vasoactive metabolites. Additional studies will examine whether the diffusion of substances from the venule to the arteriole occurs during changes in the physiological conditions of the tissue. 2) If there is sufficient diffusion of a metabolite from the venule to a crossing arteriole, is the resultant arteriolar dilation localized or is the dilation propagated upstream resulting in larger increases in blood flow? This dilation may be due to a velocity-induced mechanism. 3) Is there a velocity-dependent release of an endothelial derived factor from venules that will affect the diameter of a nearby arteriole? This information will determined by demonstrating the existence of a venular velocity-induced arteriolar vasodilation and then blocking the vasodilation through the use of available EDRF blockers. An important aspect of each of these studies will be to determine the physiological role of each of these mechanisms in regulating arteriolar diameter.