title: The effect of intra-arterial endothelin on resting blood flow and sympathetically mediated vasoconstriction in the forearm of man.
abstract: 1. The hypothesis that endothelin (ET) influences sympathetically mediated vasoconstriction was investigated in 13 healthy, male subjects. 2. ET (1 pmol min-1) was infused for 60 min into the left brachial arteries of seven healthy male subjects. Resting forearm blood flow, and sympathetic vasoconstriction produced by lower body negative pressure (LBNP; 15 mm Hg), was measured in both arms by strain gauge plethysmography. In a further six subjects, noradrenaline (NA) was infused intra-arterially at doses of 150-600 pmol min-1, with and without co-infusion of ET (1 pmol min-1), with blood flow measured in both forearms. 3. ET produced a small but significant reduction of blood flow in the infused forearm from 3.9 +/- 0.6 ml 100 ml-1 min-1 during infusion of saline, to 3.3 +/- 0.7 ml 100 ml-1 min-1 during infusion of ET at 60 min (P less than 0.05). Blood flow in the non-infused forearm was not altered by ET infusion. 4. NA produced a significant and dose-dependent reduction of blood flow in the infused forearm from 3.13 +/- 0.5 ml 100 ml-1 min-1 during saline infusion, to 1.49 +/- 0.2 ml 100 ml-1 min-1 with NA at 600 pmol min-1 (P less than 0.001). During co-infusion of ET, blood flow was reduced similarly in the infused arm from 3.15 +/- 0.7 ml 100 ml-1 min-1 during saline infusion to 1.55 +/- 0.2 ml 100 ml-1 min-1 with NA at 600 pmol min-1. Blood flow in the non-infused arm was not altered by ET and NA infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Clinical Pharmacology, London.
authors.forename: J R
authors.initials: JR
authors.lastname: Cockcroft
authors.forename: J G
authors.initials: JG
authors.lastname: Clarke
authors.forename: D J
authors.initials: DJ
authors.lastname: Webb
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000008:administration & dosage / Q000494:pharmacology*; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D007269:Injections, Intra-Arterial; D008150:Lower Body Negative Pressure; D008297:Male; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects*; D013564:Sympathetic Nervous System / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D016232:Endothelins; D009638:Norepinephrine