Fig. 6. Preservation of sarcoplasmic reticulum Ca2+levels during Ca2+depletion by the presence of sevoflurane. (A ) Time course of changes in mag-fluo-4 fluorescence intensity during Ca2+-free superfusion in the absence and presence of sevoflurane (SEVO, 3%) in Post and Postlong applications. Fluorescence intensity was normalized to its initial value just before Ca2+-free superfusion (F/F0). Inset shows the mag-fluo-4 fluorescence images recorded just before and at the end of Ca2+-free superfusion (1 and 2, respectively) in each protocol. The scale bars indicate 50 μm. (B ) Summarized data showing mag-fluo-4 F/F0measured at the end of 15 min of Ca2+depletion in Control (0.80, [0.77–0.83]; n = 21, N = 5), in Post (0.80, [0.77–0.83]; n = 22, N = 5) and Postlong (0.88, [0.84– 0.93]; n = 18, N = 5) applications. *P < 0.05 (P = 0.018 vs. Control, P = 0.022 vs. Post). (C ) Effect of sevoflurane on mag-fluo-4 fluorescence intensity during Ca2+depletion recorded in the presence of tetracaine (1 mM). (D ) Summarized data showing mag-fluo-4 F/F0measured at the end of 15 min of Ca2+-depletion in the presence of tetracaine and sevoflurane as indicated. † Tetracaine was added before sevoflurane, as indicated in C ; § sevoflurane was administered before tetracaine during initial superfusion with normal Tyrode solution. There was no significant difference among the three groups, except the Control (n = 8, N = 3 for each group). *P < 0.05 compared with Control (P = 0.038 for all *). NS = not significant.