title: Ischemia-induced alteration of myocardial Na(+)-K(+)-ATPase activity and ouabain binding sites in hypercholesterolemic rabbits.
abstract: 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.
authors.affiliation: Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: W J
authors.initials: WJ
authors.lastname: Chen
authors.forename: S Y
authors.initials: SY
authors.lastname: Lin-Shiau
authors.forename: H C
authors.initials: HC
authors.lastname: Huang
authors.forename: Y T
authors.initials: YT
authors.lastname: Lee
mesh_terms: 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*
chemical_list: C028996:cardiac glycoside receptors; D010042:Ouabain; D012964:Sodium; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium