Neuronal nitric oxide synthase is up-regulated by angiotensin II and attenuates NADPH oxidase activity and facilitates relaxation in murine left ventricular myocytes

► Ang II activated NADPH oxidase (NOX2) and prolonged LV myocyte relaxation at 30 min. ► nNOS is upregulated by Ang II (3 h), inhibited NOX2 and shortened myocyte relaxation. ► Myocyte contraction and L-type Ca2+ current density were not affected by Ang II (3 h). ► cGMP/PKG-dependent PLN-p mediated faster relaxation induced by nNOS and Ang II. ► PKA, CaMKII-pathway or peroxynitrite did not prevent the lusitropic effect of nNOS.