Fig. 4.

Normal Ca²⁺ transients and reduced Ca²⁺ spark frequency in JPH2-OE mice. (A) Representative confocal line-scan images showing Ca²⁺ sparks in ventricular myocytes from control and JPH2-OE mice. (B) Quantification showing reduced Ca²⁺ spark frequency in JPH2-OE compared to control mice. (C) Quantification showing decreased Ca²⁺ spark size in JPH2-OE mice (FWHM; n=17 cells, 3 animals both genotypes). (D) Confocal linescan images showing similar Ca²⁺ transients in ventricular myocytes from control and JPH2-OE mice. (E) Bar graph showing quantification of Ca²⁺ transient amplitude (CaT). (F) Bar graph quantifying increased SR Ca²⁺ load in JPH2-OE cardiomyocytes (control n=21, cells, 5 animals; JPH2-OE, n=26 cells, 5 animals). Data are displayed as mean±s.e.m. *P<0.05, ***P<0.001 (two-sided Student's t-test).