Bolus injection of NS 309 (10 nmol) in isolated perfused kidneys from normotensive WKY, SHR and L-NAME-treated SHR (n= 5–7). The experiments were performed in the presence of indomethacin plus L-NA. The results are shown as % dilatation of the increase in perfusion pressure induced by methoxamine and values are expressed as mean ± SEM. *P < 0.05, AUC significantly different from control; $P < 0.05, significant difference between SHR and L-NAME-treated SHR; one-way anova, followed by a Bonferroni post hoc test, three multiple comparisons.