Fig. 12.

Response of calcium transients (CaTs) in Epi and PM myocytes to changes in AP repolarization induced by intracellular acidosis (80.0 mM acetate). Control bathing solution was used for all experiments shown in this figure. A: examples of CaTs elicited by AP clamps using control and acidosis templates in Epi (a) and PM (b) myocytes. B: summary of results for amplitude (a), maximum rate of rise (b), and duration (c) of CaTs (Epi, n = 8; PM, n = 10). The acidosis template increased amplitude and maximum rate of rise of the CaT in Epi but not PM cells. The acidosis template increased CaT duration [measured as time from upstroke to 50% recovery (CaTD₅₀)] in both cell types. *P < 0.05, **P < 0.01, paired, control vs. acidosis template. CL = 2 s was used for all experiments shown in this figure.