THE EFFECT OF β-RECEPTOR BLOCKERS ON THE ISOPRENALINE INDUCED INCREASE OF HEART MUSCLE OXYGEN CONSUMPTIONS

The blockade effect of β-receptor blockers bupranolol and ACC9089 on the increase of heart muscle oxygen consumption by isoprenaline was studied according to Castellucci's method with Warburg's apparatus on thin slices of swine heart muscle instead of the rabbit heart muscle. The results showed that Bupranolol was about 2.5 times more stronger than practolol and about 2 times more stronger than ACC-9089 to block the increase of effects of isoprenaline for swine heart muscle oxygen consumptions on equal molar concentration levels. The results showed also that only the secondary higher concentration of 4 different concentrations of ACC-9089 could block the β-receptor to decrease the heart muscle oxygen consumption in comparison with the control. It was suggested that the highest molar cone. (1.72×10^-3M) of ACC-9089 would probably show an intrinsic sympathomimetic effect which could overlay its blockade effect to β-receptors. That the β-receptor blockers would act as the competitions with isoprenaline to the β-receptors according to their similarity of the side chain chemical structures has been discussed.