Melatonin inhibits nitric oxide production by microvascular endothelial cells in vivo and in vitro - Silva, C. L. M; Tamura, Eduardo Koji; Macedo, Sandra Manoela Dias; Cecon, Erika; Bueno-Alves Junior, L; Farsky, Sandra Helena Poliselli; Ferreira, Zulma S; Markus, Regina P (British Journal of Pharmacology, 2007)