Myocardial infarction alters myofilament calcium sensitivity and mechanical behavior of myocytes

Peng Li, Polly Hofmann, Baosheng Li, Ashwani Malhotra, Wei Cheng, Edmund H. Sonnenblick, Leonard G. Meggs, Piero Anversa

Research output: Contribution to journalArticle

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Abstract

To determine whether myocardial infarction leads to alterations in myofilament isometric tension as a function of Ca 2+ concentration, unloaded shortening velocity, and sarcomere compliance, these properties were examined in skinned myocytes 7 days after coronary artery occlusion. Changes in myofilament proteins were also evaluated. Myocardial infarction was characterized by a 10-15% reduction in myofilament isometric tension at submaximum Ca 2+ levels in the physiological range. However, developed tension at maximum activation was unaltered. Conversely, unloaded shortening velocity was decreased by 31% in the remaining viable cells, whereas resting tension was increased by 30-40%. The regulatory protein troponin I content was reduced, but phosphorylation of troponin I and troponin T was increased. Myosin isoenzymes and troponin T contents were not altered. In conclusion, molecular responses occurred acutely after myocardial infarction, and these adaptations may depress the mechanical behavior of the unaffected cells, contributing to acute impairment in global cardiac pump function beyond that resulting from myocyte loss.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume272
Issue number1 41-1
StatePublished - Feb 20 1997

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Myofibrils
Muscle Cells
Troponin T
Troponin I
Myocardial Infarction
Calcium
Sarcomeres
Coronary Occlusion
Myosins
Isoenzymes
Compliance
Coronary Vessels
Proteins
Phosphorylation

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Myocardial infarction alters myofilament calcium sensitivity and mechanical behavior of myocytes. / Li, Peng; Hofmann, Polly; Li, Baosheng; Malhotra, Ashwani; Cheng, Wei; Sonnenblick, Edmund H.; Meggs, Leonard G.; Anversa, Piero.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 272, No. 1 41-1, 20.02.1997.

Research output: Contribution to journalArticle

Li, Peng ; Hofmann, Polly ; Li, Baosheng ; Malhotra, Ashwani ; Cheng, Wei ; Sonnenblick, Edmund H. ; Meggs, Leonard G. ; Anversa, Piero. / Myocardial infarction alters myofilament calcium sensitivity and mechanical behavior of myocytes. In: American Journal of Physiology - Heart and Circulatory Physiology. 1997 ; Vol. 272, No. 1 41-1.
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