Inhibition of PI3K improves contractility in alpha1-adrenergically stimulated myocardium.

Recent studies have demonstrated that phosphoinositide 3-kinases (PI3Ks) play a fundamental role in regulating myocardial contractility. However, even though alpha1-adrenergic receptor stimulation is known to activate PI3Ks, the impact of this pathway on the inotropic effects of alpha1-stimulation is unclear. Isolated rabbit ventricular myocytes were preincubated with the PI3K inhibitor wortmannin (WM, 0.