EFFECT OF 3-O-ALKYL D-GLUCOSE DERIVATIVE ON EXCITATION-CALCIUM RELEASE COUPLING IN MOUSE SKELETAL-MUSCLE

We have studied the effect of non-ionic tensioactive derivative, 3-O-a lkyl 1,2,-O-isopropylidene alpha-D-glucofuranose (OR3MAG), on calcium transients and intramembrane charge movement from dissociated intercos tal muscle of mice foetuses. The variation of intracellular calcium co ncentration was measured using the fluorescent Ca2+ indicator Fura-2, and intramembrane charge movement was recorded with the patch clamp te chnique. OR3MAG (30 mu M-600 mu M) added to the bath irreversibly inhi bited the calcium transient evoked by electrical stimulation. Furtherm ore, OR3MAG immobilized intramembrane charge movement triggered by mem brane depolarization in a dose-dependent manner. We suggest that OR3MA G reduces intramembrane charge movement required for signal transducti on between the sarcolemma and the sarcoplasmic reticulum, thereby inhi biting the excitation-calcium release mechanism.