Insulin inhibits the increased contractile force induced by epinephrine in isolated guinea pig heart muscle

While the mechanism of positive inotropic action of insulin is not yet fully known, glycose, insulin and potassium solution (GIK solution) has been used in cardiopulmonary resuscitation. Catecholamines continue to be the first line drug to increase blood pressure during cardiac arrest. This study was designed to determine the interaction of insulin and epinephrine on guinea pig papillary heart muscle. The mechanical response of papillary muscle isolated from guinea pig ventricle was observed. Epinephrine increased the twitch tension with a mean maximum contractile force of 766.4% of control. Insulin decreased the increased tension induced by epinephrine to 103.8% of control. This blocking phenomena was not influenced by preadministered insulin. Likewise, the effect of epinephrine was not affected by preadministered insulin.