Fig. 2. Changes in intracellular concentration of free Ca²⁺(indicated by R^340/380) and muscle tension during contractions induced by high K⁺(72.7 mm) and carbachol (1 μm). Low temperature (31°C) and isoflurane (3%) were introduced simultaneously during the contractions. Isoflurane significantly and similarly inhibited high-K⁺– and carbachol-induced muscle contractions, with concomitant inhibition of increases in Ca²⁺.