Bradykinin-induced venodilation is not different in blacks

Aims. The aim of this study was to determine whether young, normotensive blacks who have been recently demonstrated to have a venodilator response to isoprenaline decreased compared with whites, also have an decreased vasodilatory response to bradykinin. Methods. Eleven black and 11 white subjects were studied. Full dose-response curves to bradykinin (dosing range 0.5-500 ng min^-1) were generated in hand veins preconstricted with phenylephrine (dosing range 20-6800 ng min^-1). Results. The groups had a similar maximal response to bradykinin (57.6 ± 32.2% vs 67.8 ± 49.3%, P = NS 95% confidence interval for the difference (CI): -47.3, 26.8). Also, the log of the dose that produced half maximal response to bradykinin was similar for the two groups (0.89 ± 0.58 vs 0.78 ± 0.61 ng min^-1, P = NS, 95% CI: -0.42, 0.64). There was no difference between the two groups in the log dose of phenylephrine necessary to produce 80% constriction of the hand vein. Conclusion. Diminished vasodilatory response to endothelium-derived relaxing factor (EDRF) does not seem to be associated with the increased prevalence of hypertension in blacks.