Depressed endothelium-dependent relaxation responses to acetylcholine and histamine in isolated human epigastric arteries from pre-eclamptic women.

The vasorelaxant effects of acetylcholine (Ach) and histamine have been examined on 10(-7) M-noradrenaline (NA)-precontracted ring preparations of epigastric arteries from normotensive and pregnancy-induced hypertensive women. Contractile responses to 10(-7) M-NA were significantly (p < 0.05) enhanced following removal of the endothelium. Both Ach and histamine (in the presence of H1-receptor blockers) elicited methylene blue-sensitive concentration-dependent relaxations only in endothelium-intact rings. The relaxation responses to both agents were significantly attenuated in arterial rings from pre-eclamptic women. Endothelium-independent relaxation responses induced by sodium nitroprusside were comparable in arterial rings from both patient groups. The results suggest an impairment of endothelial function in pre-eclampsia.