title: Cellular changes induced by chronic nitric oxide inhibition in intact rat basilar arteries revealed by confocal microscopy.
abstract: BACKGROUND
  Cellular aspects of remodelling have not been investigated fully in intact vessels due to lack of appropriate methodology.
  
  
  OBJECTIVE
  To determine the cellular alterations induced by chronic inhibition of nitric oxide (NO) production in intact rat basilar arteries by combined use of perfusion myography and a laser scanning confocal microscope.
  
  
  METHODS
  Wistar-Kyoto rats were treated with 10 mg/kg per day NG-nitro-L-arginine methyl ester (L-NAME) for 3 weeks. Basilar arteries from treated and age-matched Wistar-Kyoto rat controls were mounted on a perfusion myograph, stained with the nuclear dye Hoechst 33342 and fixed under pressure. The segments were mounted on a slide and visualized using the 364 nm line of a laser scanning confocal microscope. MetaMorph software was used to obtain optical sections from the vessel and for morphology determinations.
  
  
  RESULTS
  L-NAME treatment induced hypertension (systolic blood pressure control 129.2+/-2.7 mmHg and SBP L-NAME treatment 176.3+/-5.2 mmHg, P< 0.001). Compared with control rat arteries, arteries from treated rats had a reduced lumen diameter, similar wall thickness and an increased wall: lumen ratio. L-NAME treatment induced specific changes in adventitia, media and intima, namely an increase in number of adventitial cells and in adventitia thickness, a reduction in number of smooth muscle cells with no change in media thickness and reductions in number of endothelial cells, size of nuclei and luminal surface area.
  
  
  CONCLUSIONS
  Hypertension induced by chronic inhibition of NO production is associated with eutrophic remodelling of rat basilar artery. However, within this overall maintenance of constant volume, there are marked cellular changes in adventitia, media and intima. The separate contributions of inhibition of NO production and hypertension to the remodelling process need to be elucidated.
authors.affiliation: Clinical Research Initiative in Heart Failure, Institute of Biomedical & Life Sciences, University of Glasgow, UK.
authors.forename: S M
authors.initials: SM
authors.lastname: Arribas
authors.forename: C
authors.initials: C
authors.lastname: González
authors.forename: D
authors.initials: D
authors.lastname: Graham
authors.forename: A F
authors.initials: AF
authors.lastname: Dominiczak
authors.forename: J C
authors.initials: JC
authors.lastname: McGrath
mesh_terms: D000818:Animals; D001488:Basilar Artery / Q000473:pathology*; D002452:Cell Count; D004730:Endothelium, Vascular / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006973:Hypertension / Q000209:etiology / Q000473:pathology; D018613:Microscopy, Confocal; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D019001:Nitric Oxide Synthase / Q000187:drug effects; D051381:Rats; D011921:Rats, Inbred WKY
chemical_list: D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester