Fig. 1

l-Arg induced NO release from NE-MD cells. a Representative traces of NO release in normal solution (Na⁺ Ringer, top), furosemide-treated (+Furo, middle), and furosemide-treated in the presence of 7-nitroindasole (+Furo+7-NI, bottom). Arrows and arrowheads indicate the addition of normal solution and stock solutions of l-Arg, respectively. Single and double arrowheads, respectively, indicate the final concentrations of 0.2 and 1.0 mM l-Arg after dilution. b The NO concentrations released are 7.5 ± 3.6 (Na⁺ Ringer), 95.4 ± 15.2 (+Furo), and 1.0 ± 0.3 nM (+Furo+7-NI) in the presence of 1 mM l-Arg (n = 4, each). Statistical significance compared with the control values are indicated in the figure