Abbreviations
GTN Nitroglycerin or Glyceryl trinitrate
ADMA Asymmetric dimethylarginine
NO Nitric oxide, nNOS, neuronal nitric oxide synthase
eNOS endothelial nitric oxide synthase
NMMA NG-monomethyl-l-arginine (l-)
SDMA ω NG,N′G-symmetric dimethylarginine
DDAH dimethylarginine dimethylaminohydrolase
Andrea Ferrigno and Chiara Demartini contributed equally to this work.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
RG instructed the experiments, AF, CD and AZ performed the experiments. RG analysed the data and drafted the manuscript. CT revised the manuscript. All authors contributed to the idea of the study, and read and approved the final manuscript.

Acknowledgements
This study was supported by a grant from the Italian Ministry of Health to “C. Mondino” National Neurological Institute (Ricerca Corrente 2011).