EFFECT OF LIPOPHILIC IONS ON THE INTRAMEMBRANE CHARGE MOVEMENT AND INTRACELLULAR CA2-MUSCLE( RELEASE IN FETAL MOUSE SKELETAL)

The effects of lipophilic ions on the intramembrane charge movement an d intracellular calcium transient were studied using freshly dissociat ed skeletal muscle cells from mice fetuses. The lipophilic cations Rho damine 6G and tetraphenylphosphonium (TPP) immobilized part of the int ramembrane charge movement in a dose-dependent manner, and inhibited b oth calcium transient and contraction evoked by membrane depolarizatio n. In contrast, the lipophilic anion 1-anilinonaphthalene-8-sulfonic a cid (ANS) had no effect on intramembrane charge movement. We suggest t hat the lipophilic cations block the voltage-sensing mechanism for the excitation-contraction (E-C) coupling mechanism.