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Cardiac and muscle fatigue due to relative functional overload induced by excessive stimulation, hypersensitive excitation-contraction coupling, or diminished performance capacity correlates with sarcoplasmic reticulum failure.

Publication ,  Journal Article
O'Brien, PJ; Shen, H; Weiler, J; Ianuzzo, CD; Wittnich, C; Moe, GW; Armstrong, PW
Published in: Can J Physiol Pharmacol
February 1991

The development of muscle fatigue due to exhaustive exercise is associated with impaired sarcoplasmic reticulum (SR) Ca-transport activity. This study tested the hypothesis that SR failure is a consistent feature of cardiac and skeletal muscle fatigue owing to relative functional overload regardless of the method of induction: excessive stimulation, diminished performance capacity, or excessive excitation-contraction coupling. The Ca-transport activity was determined using three unique models of muscle fatigue: chronic and rapid ventricular pacing in dogs; metabolic inhibition caused by global cardiac ischemia in swine; and the hypermetabolic syndrome of porcine malignant hyperthermia (MH). Both pacing- and ischemia-induced fatigue resulted in reduction of SR Ca-transport ATPase activity: from 275 +/- 58 to 159 +/- 57 nmol.min-1.mg-1 (mU/mg) and from 577 +/- 82 to 177 +/- 133 mU/mg, respectively. Both pacing-induced fatigue and halothane-induced MH resulted in reduction of Ca-sequestration activity of muscle homogenates from 5.95 +/- 2.4 to 3.11 +/- 0.67 nM/s at 300 nM Ca and 38.7 +/- 10.5 to 16.3 +/- 8.0 nM/s at 1500 nM Ca, respectively (all p less than 0.01). The isolated SR Ca-ATPase activity correlated with Ca-sequestration activity of myocardial homogenates (r = 0.76; p less than 0.005). Different models were used to study the relationship of Ca-transport activity with relaxation function, degree of acidosis, and ionized Ca concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Duke Scholars

Published In

Can J Physiol Pharmacol

DOI

ISSN

0008-4212

Publication Date

February 1991

Volume

69

Issue

2

Start / End Page

262 / 268

Location

Canada

Related Subject Headings

  • Sarcoplasmic Reticulum
  • Physiology
  • Myocardium
  • Myocardial Contraction
  • Muscles
  • Muscle Relaxation
  • Muscle Contraction
  • Malignant Hyperthermia
  • Male
  • Lactic Acid
 

Citation

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O’Brien, P. J., Shen, H., Weiler, J., Ianuzzo, C. D., Wittnich, C., Moe, G. W., & Armstrong, P. W. (1991). Cardiac and muscle fatigue due to relative functional overload induced by excessive stimulation, hypersensitive excitation-contraction coupling, or diminished performance capacity correlates with sarcoplasmic reticulum failure. Can J Physiol Pharmacol, 69(2), 262–268. https://doi.org/10.1139/y91-040
O’Brien, P. J., H. Shen, J. Weiler, C. D. Ianuzzo, C. Wittnich, G. W. Moe, and P. W. Armstrong. “Cardiac and muscle fatigue due to relative functional overload induced by excessive stimulation, hypersensitive excitation-contraction coupling, or diminished performance capacity correlates with sarcoplasmic reticulum failure.Can J Physiol Pharmacol 69, no. 2 (February 1991): 262–68. https://doi.org/10.1139/y91-040.

Published In

Can J Physiol Pharmacol

DOI

ISSN

0008-4212

Publication Date

February 1991

Volume

69

Issue

2

Start / End Page

262 / 268

Location

Canada

Related Subject Headings

  • Sarcoplasmic Reticulum
  • Physiology
  • Myocardium
  • Myocardial Contraction
  • Muscles
  • Muscle Relaxation
  • Muscle Contraction
  • Malignant Hyperthermia
  • Male
  • Lactic Acid