Figure 8. The PDE3 antagonists milrinone and cilostamide stimulate I_Ca,L but not I_f in EDS cardiomyocytes.

A and B, milrinone and cilostamide stimulated I_Ca,L (see also inset for a more extended time scale), but I_f remains unaltered (voltage protocol identical to Fig. 6). C, in the large majority of cells I_f is not stimulated upon PDE3 antagonist application. D, the current density of the non-responding cells decreased slightly in the presence of PDE inhibitors indicating a small run down. E, a quantitative comparison of the percentage of I_f density stimulation demonstrates that I_f was stimulated by PDE2 and 4 antagonists, but not by PDE3 antagonists.