Fig. 4

l-Arg-induced NO release from NE-MD cells incubated with low [Na⁺] for 2 h. a Representative traces of NO release from the NE-MD cells in a low [Na⁺] (control) and in the presence of 7-NI. Arrows and arrowheads indicate the same meanings shown in Fig. 1. b The NO released is 4.0 ± 2.8 (low Na⁺, n = 4) and 0.5 ± 0.2 nM (+7-NI, n = 4) in the presence of 1 mM l-Arg