Cine DENSE and Manganese-Enhanced Cardiac MRI Demonstrate That ENOS Does Not Play a Determining Role in Modulating the Effects of -Adrenergic Stimulation

Moriel H. Vandsburger¹, Brent A. French¹, Xiaodong Zhong^1,2, Christopher M. Kramer¹, Frederick H. Epstein¹

Dynamic manganese-enhanced MRI and cine DENSE MRI can be used to probe calcium flux and contractile function in vivo in the mouse heart. Using these methods, we sought to elucidate the role of endothelial nitric oxide synthase (eNOS) in modulating calcium flux and contractile function. Counter to the prevailing opinion, which suggests that eNOS inhibits basal calcium flux, we found that eNOS does not play a role in modulating either calcium flux or contractile function at baseline, during β-adrenergic stimulation, or during muscarinic inhibition of β-adrenergic stimulation.