Characterization of the vasoconstrictor effect of AmV. (A) Vasoconstrictor effect of AmV (0.1-50 μg/mL) (●, n = 5) and the fractions: melittin (■, n = 5); PLA2 (Ο, n = 5); and the complex PLA2 + melittin (□, n = 5). (B) Effect of endothelium removal on AmV vasoconstrictor effect. The concentration response curve of AmV (0.1-50 μg/mL) on basal tone in endothelium-containing aorta preparations (●, n = 5), and in endothelium-denuded aorta preparations (Ο, n = 4). Vasoconstrictor effects are expressed as a percentage of the contractile response to K+ (60 mM). Data are expressed as mean ± SEM and analyzed by ANOVA followed by the Holm-Sidak post hoc test.