Dynamics of crossbridge-mediated activation in the heart

Both intracellular calcium and strongly bound crossbridges contribute to thin filament activation in the heart, but the magnitude and the duration of the effects due to crossbridges are not well characterized. In this study, crossbridge attachment was altered in tetanized ferret papillary muscles an...

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Bibliographic Details
Published in:Journal of muscle research and cell motility 2005-11, Vol.26 (4-5), p.247-257
Main Authors: Vandenboom, Rene, Weihe, Elizabeth K, Hannon, James D
Format: Article
Language:English
Subjects:
Animals
Calcium - chemistry
Calcium - metabolism
Ferrets
Heart - physiology
In Vitro Techniques
Isometric Contraction - physiology
Male
Muscular system
Mustela putorius furo
Myocardial Contraction - physiology
Papillary Muscles - chemistry
Papillary Muscles - physiology
Time Factors
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Summary:Both intracellular calcium and strongly bound crossbridges contribute to thin filament activation in the heart, but the magnitude and the duration of the effects due to crossbridges are not well characterized. In this study, crossbridge attachment was altered in tetanized ferret papillary muscles and changes in the rate constant for the recovery of force (k (TR)) and unloaded shortening velocity (V (U)) were measured to track thin filament activation. k (TR) decreased as the time the muscles spent at low levels of crossbridge attachment (shortening deactivation) increased (0.02 s=17.9+/-2.3 s(-1), 0.32 s=3.3+/-0.4 s(-1); half-time=0.052 s; P
ISSN:0142-4319
1573-2657
DOI:10.1007/s10974-005-9042-5