TY - JOUR
T1 - The rate of tension recovery in cardiac muscle correlates with the relative residual tension prevailing after restretch
AU - Campbell, Kenneth S.
AU - Holbrook, Anastasia M.
PY - 2007/4
Y1 - 2007/4
N2 - Isolated cardiac muscles generate tension more quickly at higher levels of Ca2+ activation. We investigated the molecular mechanisms underlying this effect in permeabilized rat myocardial preparations by measuring the rate of tension recovery following brief shortening/restretch perturbations. Separate series of experiments used Ca2+-activating solutions with different pH values (pH 6.75, 7.00, and 7.25) and different phosphate (Pi) concentrations (0, 2.5, and 5.0 mM added Pi) to modulate the recovery kinetics. Subsequent analysis showed that the rate of tension recovery correlated (P < 0.001) with the relative residual tension, that is, the minimum tension measured immediately after restretch normalized to the steady-state isometric tension for the experimental condition. This new finding suggests that the rate at which cardiac muscles develop force increases with the proportion of cross bridges bound to the thin filament and is strong evidence of cooperative contractile activation.
AB - Isolated cardiac muscles generate tension more quickly at higher levels of Ca2+ activation. We investigated the molecular mechanisms underlying this effect in permeabilized rat myocardial preparations by measuring the rate of tension recovery following brief shortening/restretch perturbations. Separate series of experiments used Ca2+-activating solutions with different pH values (pH 6.75, 7.00, and 7.25) and different phosphate (Pi) concentrations (0, 2.5, and 5.0 mM added Pi) to modulate the recovery kinetics. Subsequent analysis showed that the rate of tension recovery correlated (P < 0.001) with the relative residual tension, that is, the minimum tension measured immediately after restretch normalized to the steady-state isometric tension for the experimental condition. This new finding suggests that the rate at which cardiac muscles develop force increases with the proportion of cross bridges bound to the thin filament and is strong evidence of cooperative contractile activation.
KW - Cardiac contractility and energetics
KW - Muscle contraction
KW - Myocardial contractility
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U2 - 10.1152/ajpheart.00714.2006
DO - 10.1152/ajpheart.00714.2006
M3 - Article
C2 - 17189351
AN - SCOPUS:34147122743
SN - 0363-6135
VL - 292
SP - H2020-H2022
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 4
ER -