scholarly journals Influence of zinc ions on myosin ATPase activity and superprecipitation reaction of actomyosin of cardiac muscle

2011 ◽  
Vol 27 (6) ◽  
pp. 446-452
Author(s):  
K. I. Bogutska ◽  
Yu. I. Prylutskyy
Keyword(s):  
Atpase Activity ◽  
Cardiac Muscle ◽  
Myosin Atpase ◽  
Zinc Ions ◽  
Myosin Atpase Activity

Correlation between cardiac muscle myosin ATPase activity and velocity of muscle shortening

1979 ◽  
Vol 21 (3) ◽  
pp. 235-245 ◽  
Author(s):  
Rita A. Carey ◽  
Alfred A. Bove ◽  
Richard L. Coulson ◽  
James F. Spann
Keyword(s):  
Atpase Activity ◽  
Cardiac Muscle ◽  
Myosin Atpase ◽  
Myosin Atpase Activity ◽  
Muscle Shortening ◽  
Muscle Myosin

Normal cardiac myosin ATPase and mechanics in pressure overload with digitalis treatment

1978 ◽  
Vol 234 (3) ◽  
pp. H253-H259 ◽  
Author(s):  
R. A. Carey ◽  
A. A. Bove ◽  
R. L. Coulson ◽  
J. F. Spann
Keyword(s):  
Atpase Activity ◽  
Cardiac Muscle ◽  
Contractile Function ◽  
Pressure Overload ◽  
Maximum Activity ◽  
Myosin Atpase ◽  
Mechanical Function ◽  
Myosin Atpase Activity ◽  
Muscle Myosin ◽  
Normal Controls

Cardiac muscle myosin ATPase activity is depressed and contractile function impaired when the heart is subjected to a chronic pressure overload. Administering digitalis in the presence of chronic pressure overload significantly attenuates the decline in mechanical function. The current study sought to determine if the cardiac muscle myosin ATPase activity of cats treated with digitalis in the presence of pressure overload remains normal in parallel with the mechanical function. Four groups of cats were studied: normal controls (C), animals with pressure-overload hypertrophy with or without failure (HF), normal cats that received treatment with digitalis (D), and animals that received digitalis prior to and together with pressure overload (DHF). Compared to C, the maximum myosin ATPase activity of HF was significantly (P less than 0.05) depressed, but the maximum ATPase activity of D and DHF was not altered significantly (P greater than 0.05) from C. In parallel with the enzyme maximum activity, the papillary muscle isometric rate of force development was significantly (P less than 0.005) depressed in HF compared to C; D and DHF were not significantly (P greater than 0.05) different from C. It is concluded that the depression of myosin ATPase observed in HF is not present when digitalis is administered concomitant with the pressure overload.

Alterations in diaphragm contractility after nandrolone administration: an analysis of potential mechanisms

1999 ◽  
Vol 86 (3) ◽  
pp. 985-992 ◽  
Author(s):  
Michael I. Lewis ◽  
Mario Fournier ◽  
Amelia Y. Yeh ◽  
Paul E. Micevych ◽  
Gary C. Sieck
Keyword(s):  
Atpase Activity ◽  
Maximum Velocity ◽  
Interstitial Space ◽  
Myosin Atpase ◽  
Fiber Types ◽  
Intact Male ◽  
Cross Sectional ◽  
Myosin Atpase Activity ◽  
Relative Contribution

The aim of this study was to evaluate the potential mechanisms underlying the improved contractility of the diaphragm (Dia) in adult intact male hamsters after nandrolone (Nan) administration, given subcutaneously over 4 wk via a controlled-release capsule (initial dose: 4.5 mg ⋅ kg−1 ⋅ day−1; with weight gain, final dose: 2.7 mg ⋅ kg−1 ⋅ day−1). Control (Ctl) animals received blank capsules. Isometric contractile properties of the Dia were determined in vitro after 4 wk. The maximum velocity of unloaded shortening ( V o) was determined in vitro by means of the slack test. Dia fibers were classified histochemically on the basis of myofibrillar ATPase staining and fiber cross-sectional area (CSA), and the relative interstitial space was quantitated. Ca2+-activated myosin ATPase activity was determined by quantitative histochemistry in individual diaphragm fibers. Myosin heavy chain (MHC) isoforms were identified electrophoretically, and their proportions were determined by using scanning densitometry. Peak twitch and tetanic forces, as well as V o, were significantly greater in Nan animals compared with Ctl. The proportion of type IIa Dia fibers was significantly increased in Nan animals. Nan increased the CSA of all fiber types (26–47%), whereas the relative interstitial space decreased. The relative contribution of fiber types to total costal Dia area was preserved between the groups. Proportions of MHC isoforms were similar between the groups. There was a tendency for increased expression of MHC2B with Nan. Ca2+-activated myosin ATPase activity was increased 35–39% in all fiber types in Nan animals. We conclude that, after Nan administration, the increase in Dia specific force results from the relatively greater Dia CSA occupied by hypertrophied muscle fibers, whereas the increased ATPase activity promotes a higher rate of cross-bridge turnover and thus increased V o. We speculate that Nan in supraphysiological doses have the potential to offset or ameliorate conditions associated with enhanced proteolysis and disordered protein turnover.

Methyl palmoxirate increases Ca2+-myosin ATPase activity and changes myosin isoenzyme distribution in the diabetic rat heart

1985 ◽  
Vol 248 (5) ◽  
pp. E602-E606 ◽  
Author(s):  
W. H. Dillmann
Keyword(s):  
Atpase Activity ◽  
Cardiac Metabolism ◽  
Diabetic Rats ◽  
Myosin Atpase ◽  
Diabetic Rat ◽  
Glycolytic Flux ◽  
Acid Oxidation ◽  
Myosin Isoenzyme ◽  
Myosin Atpase Activity ◽  
Cardiac Ventricle

Previous studies have shown that in rats diabetes mellitus leads to a decrease in cardiac ventricle myosin V1 and an increase in myosin V3 levels. Insulin administration reverts myosin isoenzyme distribution to normal levels. It is currently unclear whether the effects of insulin on myosin isoenzyme distribution are a direct effect of the hormone or are mediated through insulin-induced alterations in cardiac metabolism. To gain further insight into this question diabetic rats received methyl palmoxirate, a potent inhibitor of long-chain fatty acid oxidation. Administration of 25 mg methyl palmoxirate X kg body wt-1 X day-1 to diabetic rats for 4 wk leads to a partial reversal of the effects of diabetes. Myosin V1 predominance is re-established and Ca2+-activated myosin ATPase activity increases by 60% (Ca2+-myosin ATPase normal rats 1.067 +/- 0.13 mumol Pi X mg protein-1 X min-1, diabetic rats 0.609 +/- 0.05 mumol Pi X mg protein-1 X min-1, diabetic + methyl palmoxirate rats 0.912 +/- 0.06 mumol Pi X mg protein-1 X min-1). The methyl palmoxirate-induced increase in myosin V1 levels and Ca2+-activated myosin ATPase activity occurred in the absence of changes in insulin and thyroid hormone levels. Methyl palmoxirate may have acted through its known inhibitory effect on cardiac beta-oxidation and/or the resultant stimulatory effect on glycolytic flux. Our findings may indicate that changes in cardiac substrate consumption can influence myosin isoenzyme predominance.

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