[Effect of ryanodine on the electrical and mechanical activity of frog atrial fibers].

The effect of ryanodine on the action potential, slow inward current and mechanical activities of frog atrial fibres was studied by means of the double sucrose gap technique. Ryanodine was shown to reduce the amplitude of the slow inward current, to cause an intracellular Ca accumulation and to decrease the tonic component of the tension.