Fig. 5. Composite curves for mixtures of halothane and sevoflurane (total anesthetic concentration of 0.6 mm) on the number of spontaneous Ca2+transients induced on initial exposure ( A ) and upon removal of anesthetic(s) ( B ). Open symbols identify data describing the effects of halothane–sevoflurane mixtures, and filled symbols identify concentrations of halothane alone. Data are mean ± SEM (n = 15 or 16). * P < 0.05 between halothane alone and halothane–sevoflurane mixtures. Solid lines are the result of linear regression of these data. Dotted lines represent the mean frequency of spontaneous release under baseline conditions.