Ischemia-induced alteration of myocardial Na(+)-K(+)-ATPase activity and ouabain binding sites in hypercholesterolemic rabbits.
The purpose of this study was to explore the effect of ischemia on the Na(+)-K(+)-ATPase activity and ouabain receptor of the myocardial sarcolemma in hypercholesterolemic rabbits. Male New Zealand white rabbits were fed with either standard chow or standard chow supplemented with 0.5% (w/w) cholesterol and 10% (w/w) coconut oil. After an 8 week feeding period, the rabbits underwent a thoracotomy and myocardial ischemia was induced by occlusion of the coronary artery. Myocardial samples from the ischemic and non-ischemic regions of the left ventricle of control and cholesterol-fed rabbits were taken for study. The cholesterol-fed group showed a decrease in both Na(+)-K(+)-ATPase activity and [3H]ouabain binding sites as compared to the control group. Ischemia caused a reduction in both Na(+)-K(+)-ATPase activity [3H]ouabain bindings sites in both control and cholesterol-fed rabbits. The combination of ischemia and hypercholesterolemia produced an additive effect, with a further decrease in both Na(+)-K(+)-ATPase activity and [3H]ouabain binding sites. Neither the activity of Mg+(+)-ATPase nor the binding affinity for [3H]ouabain was affected by either hypercholesterolemia or ischemia. These findings indicate that hypercholesterolemia may exaggerate certain aspects of functional deterioration arising during myocardial ischemia.
Chen
W J
WJ
Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Lin-Shiau
S Y
SY
Huang
H C
HC
Lee
Y T
YT
D000818:Animals; D001665:Binding Sites; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D004195:Disease Models, Animal; D006937:Hypercholesterolemia / Q000150:complications* / Q000473:pathology; D007424:Intracellular Fluid / Q000378:metabolism; D008297:Male; D017202:Myocardial Ischemia / Q000150:complications / Q000201:enzymology* / Q000473:pathology; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D010042:Ouabain / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
C028996:cardiac glycoside receptors; D010042:Ouabain; D012964:Sodium; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium