Figure 2.

C1C2 Transgenic Mice

(A) Increased C1C2 mRNA and protein were documented from 2 founder lines (L1, L2) that showed different expression levels of mRNA but similar levels of protein. (B) Transmural LV samples underwent stimulation with Iso (10 μM, 10 min) or NKH477 (AC activator; 10 μM, 10 min). Net Iso cAMP production was reduced in LV from C1C2 mice. Basal and AC-dependent cAMP showed no group differences. (C) PKA activity was unchanged by increased C1C2 expression. (D) Despite diminished Iso-stimulated cAMP production in LV from C1C2 mice, there were no group differences (C1C2 vs. Con) in LV peak +dP/dt, LV peak −dP/dt, HR, or LVP through a wide range of Iso doses. (E) Histological inspection of transmural LV samples stained with H&E and Masson’s trichrome showed normal cardiac histology without fibrosis in C1C2 mice at 8 months of age. (B to E) Con denotes transgenic negative mice. H&E, hematoxylin and eosin; HR = heart rate; Iso = isoproterenol; LV = left ventricle; LVP = LV developed pressure.