Figure 7.

Unaltered SR Calcium Handling, But Reduced TT Power, in A399S-PKI Mice

(A) Representative fluorescent tracings during 1-Hz pacing showing Ca²⁺ transient amplitudes and summary results (B). The SERCA2a activity, defined as the inverse of the decay time constant of the caffeine-induced SR Ca²⁺ dump, was increased in A399S-PKI mice (C). Representative confocal line-scan images of individual Ca²⁺ sparks (D) and summary results (E). Di-8-ANEPPS staining of ventricular myocytes isolated from WT and A399S mice showing a reduction in T-tubule (TT) power (F) and summary results (G). N = cells, and number in parentheses = animals. **p < 0.01. Abbreviations as in Figures 1, 3, and 5.