Actomyosin ATP hydrolysis occurring during muscle contraction releases inorganic phosphate [Pi ] in the myoplasm. High [Pi ] reduces force and affects force kinetics in skinned muscle fibres at low temperature. These effects decrease at high temperature, raising the question of their importance under physiological conditions. This study provides the first analysis of the effects of Pi on muscle performance in intact mammalian fibres at physiological temperature. Myoplasmic [Pi ] was raised by fatiguing the fibres with a series of tetanic contractions. [Pi ] increase reduces muscular force mainly by decreasing the force of the single molecular motor, the crossbridge, and alters the crossbridge response to fast length perturbation indicating faster kinetics. These results are in agreement with schemes of actomyosin ATPase and the crossbridge cycle including a low- or no-force state and show that fibre length changes perturb the Pi -sensitive force generation of the crossbridge cycle.

Phosphate increase during fatigue affects crossbridge kinetics in intact mouse muscle at physiological temperature / Nocella, Marta; Cecchi, Giovanni; Colombini, Barbara. - In: THE JOURNAL OF PHYSIOLOGY. - ISSN 0022-3751. - STAMPA. - 595:(2017), pp. 4317-4328. [10.1113/JP273672]

Phosphate increase during fatigue affects crossbridge kinetics in intact mouse muscle at physiological temperature

NOCELLA, MARTA;CECCHI, GIOVANNI;COLOMBINI, BARBARA
2017

Abstract

Actomyosin ATP hydrolysis occurring during muscle contraction releases inorganic phosphate [Pi ] in the myoplasm. High [Pi ] reduces force and affects force kinetics in skinned muscle fibres at low temperature. These effects decrease at high temperature, raising the question of their importance under physiological conditions. This study provides the first analysis of the effects of Pi on muscle performance in intact mammalian fibres at physiological temperature. Myoplasmic [Pi ] was raised by fatiguing the fibres with a series of tetanic contractions. [Pi ] increase reduces muscular force mainly by decreasing the force of the single molecular motor, the crossbridge, and alters the crossbridge response to fast length perturbation indicating faster kinetics. These results are in agreement with schemes of actomyosin ATPase and the crossbridge cycle including a low- or no-force state and show that fibre length changes perturb the Pi -sensitive force generation of the crossbridge cycle.
2017
595
4317
4328
Goal 3: Good health and well-being for people
Nocella, Marta; Cecchi, Giovanni; Colombini, Barbara
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1083764
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