Effect of nicotine on cardiac muscle contractions and radiocalcium movement

Abstract

Nicotine, 0.01–0.1 mm, evoked a positive inotropic response and abolished the "staircase" and poststimulation potentiation in toad ventricular muscle; 0.2 mm nicotine caused the development of contracture, whether or not extracellular Ca⁺⁺ was present; and 1.0 mm nicotine enhanced the uptake and release of Ca⁴⁵ from the muscle. It seems probable that the effect of nicotine on the contractile response of cardiac muscle can be related to the mobilization of Ca⁺⁺.