AJP - Heart and Circulatory Physiology, Vol 249, Issue 6 1093-H1097, Copyright © 1985 by American Physiological Society
Effect of chronic surgical denervation of dog heart on myocardial Na+-K+ pump
R. B. Wanless, A. J. Drake-Holland and M. I. Noble
The effect of chronic denervation of the myocardium on myocardial Na+-K+
pump activity and numbers of pump sites was studied in dogs. Right
ventricular biopsies were taken immediately before and 4 wk after chronic
surgical denervation, when depletion of norepinephrine is complete. Na+-K+
pump activity was assayed by ouabain-sensitive 86Rb uptake into ventricular
tissue slices. The number of pump sites was measured by [3H]ouabain binding
in ventricular tissue slices. Ouabain-sensitive Rb uptake was increased
after denervation by an average of 147%. [3H]-ouabain binding at a
concentration of 1.25 X 10(-6) M increased by an average of 27.6% after
denervation. Acutely applied norepinephrine (2 X 10(-7) M) stimulated
ouabain-sensitive Rb uptake both before and after denervation. The
stimulation was greater after denervation, indicating supersensitivity. The
cause of these changes is not known.
