title: L-NAME iontophoresis: a tool to assess NO-mediated vasoreactivity during thermal hyperemic vasodilation in humans.
abstract: BACKGROUND
  Decreased endothelial Nitric oxide (NO) bioavailability is one of the earliest events of endothelial dysfunction. Assessment of microvascular blood flow using a Laser Doppler Imager during local noninvasive administration of L-N-Arginine-Methyl-Ester (L-NAME) by skin iontophoresis may help discriminate the relative contributions of NO and non-NO pathways during a skin thermal hyperemic test.
  
  
  METHODS
  In healthy nonsmokers, the effects of thermal vasodilation and sodium nitroprusside-mediated vasodilation were tested on skin pretreated with 0.9% saline solution, 2% L-NAME iontophoresis (n = 12), or intradermal injection of 25 nmol L-NAME (n = 10). The effects of L-NAME iontophoresis were also measured in a group of smokers (n = 10).
  
  
  RESULTS
  L-NAME iontophoresis and intradermal injection of L-NAME decreased the skin response to local heating to a similar degree (-41% ± 4% vs. -44% ± 6%). L-NAME iontophoresis site-to-site and day-to-day coefficients of correlation were 0.83 and 0.76, respectively (P < 0.01). The site-to-site and day-to-day coefficients of correlation of L-NAME injection were lower than those of iontophoresis at 0.66 (P < 0.05) and 0.12, respectively (P = not significant). Sodium nitroprusside-induced skin hyperemia was not affected by L-NAME administration. L-NAME iontophoresis-mediated inhibition of skin thermal hyperemia was greater in smokers than in nonsmokers (P < 0.05).
  
  
  CONCLUSIONS
  Laser Doppler Imager assessment of skin thermal hyperemia after L-NAME iontophoresis provides a reproducible and selective bedside method of qualitatively analyzing the contribution of the NO pathway to microvascular vasomotor function.
authors: Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium.
authors: Céline
authors: C
authors: Dreyfuss
authors: Aurélien
authors: A
authors: Wauters
authors: Dionysios
authors: D
authors: Adamopoulos
authors: Stéphanie
authors: S
authors: Pochet
authors: Mohamed
authors: M
authors: Azarkan
authors: Guy
authors: G
authors: Berkenboom
authors: Philippe
authors: P
authors: van de Borne
authors: Jean François
authors: JF
authors: Argacha
mesh_terms: D000328:Adult; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D005240:Feasibility Studies; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D006979:Hyperthermia, Induced; D007271:Injections, Intradermal; D007478:Iontophoresis; D017078:Laser-Doppler Flowmetry; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000008:administration & dosage; D009599:Nitroprusside / Q000008:administration & dosage; D015203:Reproducibility of Results; D015398:Signal Transduction; D012867:Skin / Q000098:blood supply*; D012907:Smoking / Q000009:adverse effects / Q000503:physiopathology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D055815:Young Adult
chemical_list: D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester