Figure 4.

Effect of P4-BSA on BPA-induced alterations of Ca²⁺ handling and PLN17 phosphorylation in female rat ventricular myocytes. (a) Representative recordings of Ca²⁺ sparks in quiescent myocytes under control and various treatments as indicated. (b) Mean Ca²⁺ sparks frequency under various treatments (n = 8 to 9 myocytes from four hearts). (c) Percentages of myocytes with triggered activities under various treatments (n = 35 to 45 myocytes from four hearts). (d and e) Representative immunoblot and quantification of PLN17 phosphorylation and total PLN under control and indicated treatments. All values were normalized to control (n = 3 hearts). BPA, P4, and P4-BSA = 1 nM; RU486 = 1 μM for all experiments. **P < 0.01; ^#P > 0.1 versus control (one-way analysis of variance or χ² test). NS, not significant. Error bars are standard error of the mean.