scholarly journals The economy of isometric force development, myosin isoenzyme pattern and myofibrillar ATPase activity in normal and hypothyroid rat myocardium.

1985 ◽  
Vol 56 (1) ◽  
pp. 78-86 ◽  
Author(s):  
C Holubarsch ◽  
R P Goulette ◽  
R Z Litten ◽  
B J Martin ◽  
L A Mulieri ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Isometric Force ◽  
Isoenzyme Pattern ◽  
Rat Myocardium ◽  
Myofibrillar Atpase ◽  
Force Development ◽  
Myosin Isoenzyme ◽  
Myofibrillar Atpase Activity

Influence of verapamil on some subcellular defects in diabetic cardiomyopathy

1989 ◽  
Vol 256 (4) ◽  
pp. E453-E458 ◽  
Author(s):  
N. Afzal ◽  
G. N. Pierce ◽  
V. Elimban ◽  
R. E. Beamish ◽  
N. S. Dhalla
Keyword(s):  
Atpase Activity ◽  
Diabetic Cardiomyopathy ◽  
Diabetic Rats ◽  
Myosin Atpase ◽  
Myofibrillar Atpase ◽  
Sprague Dawley ◽  
Myosin Isoenzyme ◽  
Myofibrillar Atpase Activity ◽  
Sprague Dawley Rats ◽  
Ventricular Tissue

The effects of verapamil on cardiac myofibrillar adenosinetriphosphatase (ATPase) activity, myosin ATPase, and myosin isoenzyme profile as well as sarcoplasmic reticular Ca2+ uptake and ATPase activities were examined in Sprague-Dawley rats made diabetic with a single injection of streptozotocin (65 mg/kg). Myofibrillar ATPase activity and myosin Ca2+ ATPase activity as well as Ca2+ uptake and Ca2+-stimulated ATPase activities of the sarcoplasmic reticulum were significantly decreased in diabetic hearts in comparison to the control values. The myosin isoenzyme component V3 was prominent in diabetic hearts, whereas V1 isoenzyme was the major myosin component in control hearts. Chronic treatment of diabetic rats with verapamil (8 mg/kg daily for 4-8 wk) resulted in an improvement of the altered myofibrillar ATPase activity, myosin ATPase, myosin isoenzyme distribution, and sarcoplasmic reticular Ca2+-pump activities in ventricular tissue. The ability of verapamil to normalize the observed defects in the subcellular organelles in diabetic cardiomyopathy may be related to its effects in controlling the entry of Ca2+ into the cardiac cell.

A Study on the Cardiac Myofibrillar ATPase Activity in Diabetic Rats

1987 ◽  
Vol 17 (3) ◽  
pp. 479
Author(s):  
Wang Seong Ryu ◽  
Un Ho Ryoo ◽  
Jung Don Seo ◽  
Young Woo Lee
Keyword(s):  
Atpase Activity ◽  
Diabetic Rats ◽  
Myofibrillar Atpase ◽  
Myofibrillar Atpase Activity

Coordination of cardiac myofibrillar and sarcotubular activities in rats exercised by swimming

1984 ◽  
Vol 247 (6) ◽  
pp. H909-H915 ◽  
Author(s):  
E. D. Pagani ◽  
R. J. Solaro
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Functional Activity ◽  
Storage Capacity ◽  
Training Effect ◽  
Myofibrillar Atpase ◽  
Transport Activity ◽  
Cross Bridge ◽  
Myofibrillar Atpase Activity ◽  
The Mean

We measured the functional activity of both myofibrils and fragmented sarcoplasmic reticulum (FSR) in microsomal fractions and homogenates of hearts of sedentary rats and rats exercised by swimming 75 min twice daily for 8 wk. Ca2+ transport was measured under conditions that restricted uptake of Ca2+ to the SR vesicles in the homogenates or microsomal fractions. There was a significant increase in myosin Ca2+-ATPase activity of myofibrils prepared from hearts of swimmers, indicating that a “training effect” had occurred. The mean rate of Ca2+ transport and mean storage capacity were the same for SR vesicles in the homogenates and microsomal fractions from hearts of controls and swimmers. At the same free Ca2+ concentration, the velocity of Ca2+ transport by FSR in homogenate preparations was inversely related to the myofibrillar ATPase activity in a series of preparations from hearts of swimmers, but there was little correlation between the same activities measured in preparations from a series of sedentary rats. Our results suggest that the increase in the rate of relaxation of hearts from exercised rats is not due to an increase in the rate of Ca2+ transport by the SR but may be due to other factors, which include an increase in the rate of cross-bridge cycling or an alteration in the relation and coordination between cross-bridge cycling and SR Ca2+ transport activity.

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