Positive inotropic effect of insulin on rabbit auricle in vitro.
Water soluble pig insulin (4 x 10(-8) to 4 x 10(-7) g/ml) produced a marked and long-lasting increase in the contractile force of the rabbit auricle in vitro. Once the maximum effect for a given insulin concentration had been reached, addition of more insulin did not produce any further increase in inotropic effect. Insulin was without effect in reserpinized animals. Inhibition of cardiac beta-receptors by propranolol suppressed the positive inotropic effect of insulin. These findings support the hypothesis that insulin releases catecholamines from the myocardium.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D012110:Reserpine / Q000494:pharmacology; D013268:Stimulation, Chemical; D013552:Swine; D013997:Time Factors
D000319:Adrenergic beta-Antagonists; D007328:Insulin; D012110:Reserpine; D011433:Propranolol