Phosphodiesterase inhibitors and the cardiac sarcoplasmic reticulum calcium release channel: differential effects of milrinone and enoximone

Abstract

Activation of the calcium release channel probably contributes to the positive inotropic action in vivo of milrinone but not enoximone. Other drugs which activate the calcium release channel have been shown to be cardiotoxic, but it is not known whether this is a specific effect of channel activation or a more general result of raising cytoplasmic calcium concentration within the myocyte. Further research is required to determine accurately the mechanism of action of drugs with phosphodiesterase inhibitory activity.