The enhancement in HUVEC migration induced by L-NAME is reverted by the NO donor DETA-NO and is independent of the cGMP pathway.

(A) HUVECs were treated for 48 h with 5 mM L-NAME in the absence or in the presence of 500 nM DETA/NO for the last 24 h, as indicated. Chemotaxis experiments were then performed using 25 ng/ml VEGF as attractants. Results are expressed as the number of migrating cells. #p<0.001 vs basal migration in control cells (CTRL); §p<0.01 vs VEGF-induced migration in control cells; ***p<0.001 vs basal migration in L-NAME treated cells; °°°p<0.001 vs VEGF-induced migration in L-NAME treated cells; no significant differences between control and DETA/NO treated cells (One-way ANOVA with Bonferroni's test, n = 15). (B) HUVECs were treated for 48 h with 5 mM L-NAME or 1 µM ODQ, and chemotaxis experiments were performed as described in (A). Results are expressed as the number of migrating cells in the different experimental conditions. #p<0.001 vs basal migration in control cells (CTRL); §p<0.001 vs VEGF-induced migration in control cells; no significant differences between control and ODQ treated cells (One-way ANOVA with Bonferroni's test, n = 3). (C) cGMP accumulation in HUVECs treated for 48 h with L-NAME or ODQ was evaluated by EIA and expressed as pmol of cGMP normalized to the cell protein content (pmol/mg protein). ***p<0.001; One-way ANOVA with Bonferroni's test; n = 3.