Figure 6. Preservation of βAR signaling through targeted PI3K inhibition is associated with preservation of capillary density and SERCA2a levels.

(A) Representative staining of cardiac sections with H&E (magnification, ×400), MT (magnification, ×20), and endothelial alkaline phosphatase (to determine capillary density; magnification, ×400) after 1 week of training. (B) Quantification of capillary density in cardiac sections stained for endothelial alkaline phosphatase expressed as percent reduction from control (n = 4–6 hearts per group). **P < 0.01 versus control, swimming, and iTACγ_inact; Student’s t test with Bonferroni correction. (C) Immunoblotting analysis of SERCA2a, actin, and PI3Kγ_inact protein levels in hearts from experimental design II. Densitometric quantification of SERCA2a levels is shown in the bottom panel (n = 6–10 per group). *P < 0.05 versus control, ^†P < 0.05 versus iTAC, ANOVA with Neuman-Keuls correction.