A chloride channel blocker prevents the suppression by inorganic phosphate of the cytosolic calcium signals that control muscle contraction.

ABSTRACT:

Key points

Accumulation of inorganic phosphate (P_i ) may contribute to muscle fatigue by precipitating calcium salts inside the sarcoplasmic reticulum (SR). Neither direct demonstration of this process nor definition of the entry pathway of P_i into SR are fully established.  We showed that P_i promoted Ca²⁺ release at concentrations below 10 mm and decreased it at higher concentrations. This decrease correlated well with that of [Ca²⁺ ]_SR .  Pre-treatment of permeabilized myofibres with 2 mm Cl^- channel blocker 9-anthracenecarboxylic acid (9AC) inhibited both effects of P_i .  The biphasic dependence of Ca²⁺ release on [P_i ] is explained by a direct effect of P_i ac

SUBMITTER: Ferreira JJ 

PROVIDER: S-EPMC7775353 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature