Decrease in heart contractility produced by ouabain in fibers exposed to theophylline
De Mello, W.C.; Gonzalez-Castillo, M.
Research Communications in Chemical Pathology and Pharmacology 28(3): 387-397
1980
ISSN/ISBN: 0034-5164 PMID: 7403655 Document Number: 155940
The influence of theophylline on the inotrophic action of ouabain was investigated in strips of mammalian cardiac muscle. It was found that ouabain (2 X 10(-6) M) when added to preparations previously exposed to theophylline (4 mM) reduced the peak tension by 56%, the rate of tension development (dF/dt)max by 44% and the rate of twitch relaxation (dR/dt) by 65%. The possible mechanisms involved on the negative inotropic action of ouabain are discussed.