Endothelial cells as vascular salt sensors.
Dietary sodium and potassium contribute to the control of the blood pressure. Endothelial cells are targets for aldosterone, which activates the apically located epithelial sodium channels. The activity of these channels is negatively correlated with the release of nitric oxide (NO) and determines endothelial function. A mediating factor between channel activity and NO release is the mechanical stiffness of the cell's plasma membrane, including the submembranous actin network (the cell's 'shell'). Changes in plasma sodium and potassium, within the physiological range, regulate the viscosity of this shell and thus control the shear-stress-dependent activity of the endothelial NO synthase located in the shell's 'pockets' (caveolae). High plasma sodium gelates the shell of the endothelial cell, whereas the shell is fluidized by high potassium. Accordingly, this concept envisages that communications between extracellular ions and intracellular enzymes occur at the plasma membrane barrier, whereas 90% of the total cell mass remains uninvolved in these changes. Endothelial cells are highly sensitive to extracellular sodium and potassium. This sensitivity may serve as a physiological feedback mechanism to regulate local blood flow. It may also have pathophysiological relevance when sodium/potassium homeostasis is disturbed.
Oberleithner
Hans
H
Medical Faculty, Institute of Physiology II, University of Münster, 48149 Münster, Germany. oberlei@uni-muenster.de
Kusche-Vihrog
Kristina
K
Schillers
Hermann
H
D000450:Aldosterone / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure; D001808:Blood Vessels / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D053503:Epithelial Sodium Channels / Q000378:metabolism; D006439:Hemodynamics; D006706:Homeostasis; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D012492:Salts / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride / Q000378:metabolism; D013314:Stress, Mechanical
D053503:Epithelial Sodium Channels; D012492:Salts; D009569:Nitric Oxide; D012965:Sodium Chloride; D000450:Aldosterone; D012964:Sodium; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D011188:Potassium