We evaluated the effects of the B2-receptor antagonist Ac-D-Arg[Hyp3,D-Phe7,Leu8]-bradykinin on mean blood pressure (MBP) and Doppler mesenteric blood flow (DMBF). The antagonist, at a dose able to completely block the hemodynamic effects of exogenous bradykinin, increased MBP by 3 +/- 1% and decreased DMBF by 12 +/- 3%. These responses persisted after pharmacological neuro-hormonal blockade. Our results suggest that the kallikrein-kinin system plays a role in the regulation of mesenteric blood flow in rats.