Figure 7.

SERCA2a or JPH2 overexpression in post-MI cells do not restore the confinement of the β₂AR-dependent cAMP response but the loss of confinement can be mimicked by PTX treatment of control cells. (A) images of cardiomyocytes indicating areas of interest (coloured ovals) situated at various distances from the point of stimulation (white arrows) where FRET was measured after local selective stimulation of β₂ARs; Scale bar, 20 µm; (B) colour-coded curves of FRET response corresponding to the four areas of interest as indicated on the right panels; from top to bottom: Local FRET in cardiomyocytes isolated from a heart with chronic MI after SERCA2a gene therapy N/n = 4/14; Local FRET in cardiomyocytes from a heart with chronic MI overexpressing JPH2 N/n = 2/7 (n = 7, from two animals); Local FRET in normal cardiomyocytes treated with PTX N/n = 3/9. (C) Differences of the relative β₂AR-cAMP levels at progressive distances from the point of original agonist application, average of N = 5/n = 1 each. N, number of animals; n, number of cells.