Does dopamine act on myocardial cells?
We examined the electrophysiological effects of dopamine on the single myocardial cells isolated from the rat and rabbit heart. Dopamine at a concentration of 1 or 10 microM did not affect the L-type Ca2+ current (ICa) or the transient outward current (ITO) in rat ventricular, rabbit atrial, ventricular, and sinoatrial node cells. It did not induce any detectable change in the action potential configuration of the rabbit ventricular cells either. We conclude that dopamine does not directly act on myocardial cells at least in terms of the electrophysiological properties.