Evidence against a role of (Na+ + K+)-ATPase in the alpha-adrenoceptor mediated positive inotropic effect of phenylephrine.
Phenylephrine (0.1-100 microM) in the presence of 1 microM propranolol increased the force of contraction in electrically driven papillary muscles from cats. This presumably alpha-adrenoceptor mediated positive inotropic effect of phenylephrine occurred without any influence on (Na+ + K+)-ATPase activity.
D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D007700:Kinetics; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000201:enzymology*; D010656:Phenylephrine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D016276:Ventricular Function
D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D011433:Propranolol; D000254:Sodium-Potassium-Exchanging ATPase