1 the time course of the positive inotropic effect of theophylline was compared with the time course of the uptake and release of [ ( 3 ) h ] -theophylline in guinea-pig isolated , electrically driven hearts perfused by the langendorff method.2 formation of theophylline metabolites could not be detected under the experimental conditions used.3 theophylline entered myocardial tissue very rapidly in two different phases .
C0018787
hearts
C0027061
myocardial tissue