The Isoforms of Na,K-ATPase in Myocardial Tissues of the Milan Hypertensive Rat

The involvement of Na, K-ATPase in the etiology of essential hypertension has been demonstrated in a limited number of cases (Diez et al., 1987). Changes in the regulation of Na, K-ATPase may be the cause or an effect of the hypertension. Alterations in NA, K-ATPase mRNA abundance in deoxycorticosterone (DOC)/high salt- or angiotensin II (A II)-treated animal models of hypertension have also been reported, where a 2-3-fold increase in the abundance of both α1 and β1 isoform mRNAs (in aorta and skeletal muscle tissues) and a 3-15-fold decrease in the abundance of α2 and α3 isoform mRNAs (in aorta and left ventricle) were found (Herrera et al., 1988). These results suggested that the increase in α1 and β1 isoforms was due to increased Na influx into the cells of the tissues concerned, whereas the decrease in the α2 and a3 isoforms was directly related to increases in vascular pressure.