Myocardial Na+-K+-ATPase activity and [3H]ouabain binding sites in hypertensive rats
Journal
European Journal of Pharmacology
Journal Volume
169
Journal Issue
1
Pages
67-74
Date Issued
1989
Author(s)
Shoei-Yn Lin Shiau
Abstract
Na+-K+-ATPase activity and [3H]ouabain binding were studied in cardiac ventricles of single wrapped kidney and DOCA-NaCl hypertensive rats. It was found that the total Na+-K+-ATPase activity decreased in the DOCA-NaCl and kidney wrapped hypertensive rats. The decrease of enzyme activity in DOCA-NaCl hypertensive rats was due to extracellular fluid expansion induced by NaCl loading, as DOCA itself had no effect on the enzyme. All these alterations were specific for Na+-K+-ATPase, since Mg2+-ATPase and 5'-nucleotidase activities were unaffected. Binding studies with [3H]ouabain showed that the decrease in Na+-K+-ATPase activity was due to a reduction in the number of binding sites for ouabain rather than to a change of binding affinity. The reduced myocardial Na+-K+-ATPase activity observed in these two types of low renin hypertension, coupled with the observation of reduced vascular Na+ pump activity by others, suggests a common underlying defect in the cardiovascular Na+-K+ transport system of these hypertensive rats.
SDGs
Type
journal article