VENULAR-ARTERIOLAR COMMUNICATION IN THE MICROCIRCULATION

流向外周循环的血液被设计成协调 根据组织的需要输送营养。 的任何增加 需要发生的血液流动是小动脉增加的结果， 直径.这种小动脉扩张可能是由于一种或多种 从组织中释放的血管活性代谢物。 的机制 小动脉从组织接收血管舒张信号是未知的。 本提案中描述的研究旨在确定 在小静脉和小动脉之间有这样的联系， 来调节小动脉直径 具体假设涉及以下问题和测量： 1)血管活性代谢物是否会从小静脉扩散到 小动脉浓度足以影响小动脉直径？ 这 将通过确定定性和定量的小动脉 在灌注相邻小静脉期间， 血管活性代谢物。 其他研究将检查是否 物质从小静脉扩散到小动脉， 组织生理条件的变化。 2)如果代谢物从小静脉到微静脉有足够的扩散， 交叉小动脉，是局部的小动脉扩张，还是 扩张向上游传播，导致血液中 流动？ 这种扩张可能是由于速度引起的机制。 3)是否存在内皮衍生因子的速度依赖性释放 会影响附近小动脉的直径 这 信息将通过证明存在微静脉来确定， 速度引起的小动脉血管舒张，然后阻断血管舒张 通过使用可用的EDRF阻断剂。 每项研究的一个重要方面是确定 这些机制中的每一种在调节小动脉 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.