Abstract
Background - Contractile dysfunction develops in the chronically instrumented canine myocardium after bouts of low-flow ischemia and persists after reperfusion. The objective of this study is to identify whether changes in the phosphorylation state of myosin-binding protein C (MyBP-C) are a potential cause of dysfunction. Methods and Results - During low-flow ischemia, MyBP-C is dephosphorylated, and the number of actomyosin cross-bridges in the central core of the sarcomere decreases as thick filaments dissemble from the periphery of the myofibril. During reperfusion, MyBP-C remains dephosphorylated, and its degradation is accelerated. Conclusions - Dephosphorylation of MyBP-C may initiate changes in myofibril thick filament structure that decrease the interaction of myosin heads with actin thin filaments. Limiting the formation of actomyosin cross-bridges may contribute to the contractile dysfunction that is apparent after low-flow ischemia. Breakdown of MyBP-C during reperfusion may prolong myocardial stunning.
Original language | English (US) |
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Pages (from-to) | 906-912 |
Number of pages | 7 |
Journal | Circulation |
Volume | 111 |
Issue number | 7 |
DOIs | |
State | Published - Feb 22 2005 |
Keywords
- Contractility
- Ischemia
- Myocytes
- Myosins
- Phosphorylation
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Physiology (medical)