Affiliation:
1. Department of Human Physiology, School of Medicine, University of California, Davis 95616.
Abstract
Albumin is required in vascular perfusates to maintain the normal permeability of microvessel walls. The most common mechanism proposed for action of albumin involves binding to the endothelial cell surface to increase the resistance to water and solute flows through hydraulic pathways across the capillary wall. The results of the present experiments do not conform to this simple adsorption model. Ringer perfusion increased the hydraulic conductivity (Lp) of the wall of single perfused frog mesenteric microvessels by 4.0 +/- 0.5-fold. The increase in Lp was associated with an increase of cytoplasmic calcium concentration ([Ca2+]i) from 59 +/- 5 nM when albumin was in the perfusate to a transient peak of 181 +/- 13 nM, 1–2 min after Ringer perfusion. [Ca2+]i then fell back to close to 100 nM. Processes that reduced Ca2+ influx into endothelial cells (removal of extracellular Ca2+, membrane depolarization) reduced Ca2+ influx and attenuated the increase in [Ca2+]i. The same processes abolished the increase in Lp after Ringer perfusion and restored Lp to close to control values during Ringer perfusion. Thus Ca2+ entry into endothelial cells is required to initiate and maintain the increased permeability during Ringer perfusion.
Publisher
American Physiological Society
Subject
Physiology (medical),Cardiology and Cardiovascular Medicine,Physiology
Cited by
66 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献