title: Oral L-arginine supplementation and cutaneous vascular responses in patients with primary Raynaud's phenomenon.
abstract: OBJECTIVE
  To assess the effects of oral L-arginine supplementation on cutaneous vascular responses in patients with primary Raynaud's phenomenon (RP).
  
  
  METHODS
  Double-blind, crossover comparison of placebo versus L-arginine (8 gm/day for 28 days). Cutaneous vascular responses in the fingers were assessed during iontophoresis of acetylcholine and sodium nitroprusside, which are endothelium-dependent and endothelium-independent vasodilators.
  
  
  RESULTS
  In comparison with control subjects, patients with primary RP had diminished endothelium-dependent and -independent vasodilatation (P < 0.05, and P < 0.005, respectively, by analysis of variance). At the 3 doses used, vascular responses to acetylcholine were reduced by 71%, 64%, and 63%, respectively, and responses to sodium nitroprusside were reduced by 67%, 73%, and 66%, respectively. L-arginine had no significant effect on cutaneous vascular responses to acetylcholine or sodium nitroprusside in control subjects or patients with primary RP.
  
  
  CONCLUSIONS
  Reduced vasodilator ability in primary RP is unlikely to be due to an impairment in the L-arginine/nitric oxide pathway.
authors.affiliation: University Department of Medicine, Ninewells Hospital and Medical School, Dundee, Scotland, UK.
authors.forename: F
authors.initials: F
authors.lastname: Khan
authors.forename: S J
authors.initials: SJ
authors.lastname: Litchfield
authors.forename: M
authors.initials: M
authors.lastname: McLaren
authors.forename: D J
authors.initials: DJ
authors.lastname: Veale
authors.forename: R C
authors.initials: RC
authors.lastname: Littleford
authors.forename: J J
authors.initials: JJ
authors.lastname: Belch
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000284:Administration, Oral; D000328:Adult; D001120:Arginine / Q000008:administration & dosage*; D004311:Double-Blind Method; D004361:Drug Tolerance; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood; D009599:Nitroprusside / Q000494:pharmacology; D010349:Patient Compliance; D010919:Placebos; D011928:Raynaud Disease / Q000503:physiopathology*; D012867:Skin / Q000098:blood supply*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D010919:Placebos; D014665:Vasodilator Agents; D009599:Nitroprusside; D009569:Nitric Oxide; D001120:Arginine; D000109:Acetylcholine