Fig. 11. (A ) Tetracaine-induced increase of intracellular Ca²⁺concentration ([Ca²⁺]ⁱ). PC12 cells were loaded with 3 μm Fluo-3 AM for 120 min and treated with (filled circles) or without (open circles) 1 mm tetracaine for indicated times. (B ) Effects of chelators on tetracaine-induced increase in [Ca²⁺]ⁱ. EGTA (1 mm) or BAPTA-AM (5 μm) was added in the loading media for the last 30 min (EGTA +) or 60 min (BAPTA-AM +), and then cells were exposed to 1 mm tetracaine (+) or culture media (−) for 15 min. [Ca²⁺]ⁱ(as fluorescent intensity units) was measured. Data are mean ± SD from two different experiments, each performed in duplicate. ***P < 0.0001 versus  control (A ), *P < 0.05 versus  only presence of tetracaine, ***P < 0.0001 versus  only presence of tetracaine (B ).