Fig. 3. Effect of FK506 on halothane-induced Ca2+release. Ca2+release in 1.0 mg sarcoplasmic reticulum terminal cisternae vesicles/ml was monitored using fluo-3 as a Ca2+indicator. (A ) Ca2+release initiated by addition of 0.4% (vol/vol) halothane. (B ) The rate of Ca2+release induced by different concentrations of halothane in control vesicles (□) or pretreated with 25 μm FK506 (•) as described in figure 2. The data are representative of four independent experiments. The data represent the mean ± SD; n = 4 independent experiments.