Effect of shear stress on surface membrane potassium ion permeability of calf pulmonary artery endothelial cells (Potassium ion)

[摘要] This study aims to determine the effect of shear stress on membrane potassium (K$sp+$) permeability in vascular endothelial cells. Cultured monolayers of calf pulmonary artery endothelial cells, preloaded with $m sp{86}Rbsp+$, were subjected to different levels of fluid shear stress in the range 1-10 dynes/cm$sp2$, in a parallel-plate geometry flow chamber, and the radioactivity of the effluent was monitored with time. Increase in laminar shear stress, from 1 dyne/cm$sp2$ to a higher level, resulted in a rapid transient increase in the rate constant for $m sp{86}Rbsp+$ release. The difference of efflux rate coefficients, between the peak and the baseline at 1 dyne/cm$sp2$, varied with shear stress in a ;;dose-dependent;; manner. Changes in K$sp+$ permeability may occur via activation of shear-stress-activated K$sp+$ channels, Ca$sp{2+}$-activated K$sp+$ channels, or both. The Ca$sp{2+}$-activated K$sp+$ channels were shown to respond to bradykinin stimulation under flow conditions. The significance of such flow studies is that they provide more knowledge about the flow-associated changes in ionic channels and intracellular second messengers in endothelial cells.

[发布机构] Rice University

[效力级别] engineering