the positive inotropic response to ro 13-6438 of the isolated guinea pig papillary muscle was accompanied by inhibition of myocardial phosphodiesterase ( pde ) activity and elevation of intracellular cyclic amp ( camp ) levels ro 13-6438 had no effect on na+ , k+-stimulated or ca2+-stimulated atpase activity and did not influence the rate of 45ca uptake in cardiac membrane vesicles .
C0030352
papillary muscle
C0027061
myocardial