title: Ouabain and responses to endothelium-dependent vasodilators in the human forearm.
abstract: Ouabain inhibits endothelium-dependent vascular relaxation in vitro, but has not been studied in this regard in vivo. We have therefore measured blood flow responses to carbachol, bradykinin and sodium nitroprusside (endothelium-dependent and endothelium-independent vasodilators) infused into the brachial artery with and without co-infusion of ouabain (2 micrograms min-1). Six healthy male volunteers were each studied on two occasions. Ouabain reduced basal forearm blood flow, by 18.0 +/- 4.1% (mean +/- s.e. mean, 2P less than 0.05), but had no significant effect on responses to any of the three vasodilators. These results indicate that effects of ouabain on endothelium-dependent relaxation in vitro must be interpreted with caution.
authors.affiliation: Department of Physiology, St Thomas' Campus, United Medical School, London.
authors.forename: R G
authors.initials: RG
authors.lastname: Woolfson
authors.forename: N
authors.initials: N
authors.lastname: Benjamin
authors.forename: S D
authors.initials: SD
authors.lastname: Todd
authors.forename: L
authors.initials: L
authors.lastname: Poston
authors.forename: J M
authors.initials: JM
authors.lastname: Ritter
mesh_terms: D000328:Adult; D001916:Brachial Artery; D001920:Bradykinin / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D005542:Forearm / Q000098:blood supply; D006801:Humans; D007261:Infusions, Intra-Arterial; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects
chemical_list: D009599:Nitroprusside; D009569:Nitric Oxide; D010042:Ouabain; D002217:Carbachol; D001920:Bradykinin