Na,K-ATPase and Ca-ATPase activities of the myocardial sarcolemma in aging rats after aorta coarctation: role of invertors.
In this work we used aorta coarctation as a model of myocardial hypertrophy. We studied the role of intracellular regulators of plasma membrane status-invertors-in the mechanisms of changes of membrane enzyme activities in the emergency stage of myocardial hypertrophy. We used Wistar rats of various ages: adult (6-8 months) and old (26-28 months) rats. It was shown that 4-6 days after aorta coarctation, in adult rats the activities of both Na,K-ATPase and Ca-ATPase of the sarcolemma of cardiomyocytes increased, but in old rats only the Ca-ATPase activity. Experiments with cell hybrids (cytosol of experimental rats and isolated sarcolemma of cardiomyocytes of intact rats) revealed that cytosol of cardiomyocytes of adult animals after aorta coarctation activated Na, K-ATPase and Ca-ATPase. Cytosol of old intact animals after aorta coarctation did not activate Na,K-ATPase, but activated Ca-ATPase. It was supposed that 4-6 days after aorta coarctation, intracellular regulators (invertors) activating Na,K-ATPase and Ca-ATPase of rat sarcolemma were synthesized in cytosol of adult animals. Invertors activating Na,K-ATPase did not appear after the aorta coarctation in old animals, but factors activating Ca2+-ATPase appeared. Cytosol of adult experimental rats activated Na,K-ATPase of sarcolemmas of cardiomyocytes of intact old animals. The data proved the ability of Na,K-ATPase of sarcolemma of old animals to respond to regulating factors. Based on the divergence between the results of experiments with the Na,K-ATPase and Ca-ATPase activities in old rats, it can be supposed that we were dealing with two different invertors.
Institute of Gerontology, Academy of Medical Sciences of Ukraine, Kiev, Ukraine. direct@geront.freenet.kiev.ua
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Frolkis
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Kobzar
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Pugach
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001017:Aortic Coarctation / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D006332:Cardiomegaly / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D004789:Enzyme Activation; D009206:Myocardium / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D012508:Sarcolemma / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase