title: The use of an in vivo model to study the effects of hyperhomocysteinaemia on vascular function.
abstract: OBJECTIVE
  To use an in vivo rat model of hyperhomocysteinaemia (HHCy) to study its impact on vascular function.
  
  
  METHODS
  Twenty rats were fed either a control or HHCy-inducing diet for 10 wk. The response of aortic rings to contraction with phenylephrine, and relaxation to acetylcholine (endothelium-dependant relaxation) or sodium nitroprusside (endothelium-independent relaxation) was analyzed. The results were compared using an analysis of variance (ANOVA).
  
  
  RESULTS
  There was a significant elevation of HCy in the treated group (20.5 versus 1.6 micromol/L, P = 0.004). There was no significant difference between the two groups in blood pressure measurements (ANOVA, P = 0.152). In a dose-dependant manner, phenylephrine elicited significantly greater contraction in aorta taken from HHCy rats than that taken from controls (ANOVA, P < 0.001), acetylcholine elicited significantly less percentage relaxation in aorta taken from HHCy rats than from controls (ANOVA, P = 0.003) and though sodium nitroprusside stimulated less percentage relaxation in aorta taken from HHCy rats than controls, this did not reach significance (ANOVA, P = 0.051).
  
  
  CONCLUSIONS
  In diet induced hyperhomocysteinaemic rats, there is enhanced vascular contraction in response to phenylephrine and impaired endothelium-dependant relaxation in response to acetylcholine.
authors.affiliation: Northern Vascular Unit, Freeman Hospital, Newcastle upon Tyne, United Kingdom.
authors.forename: Monica
authors.initials: M
authors.lastname: Hansrani
authors.forename: Gerard
authors.initials: G
authors.lastname: Stansby
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology; D005492:Folic Acid; D020138:Hyperhomocysteinemia / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D008715:Methionine; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; D005492:Folic Acid; D008715:Methionine; D000109:Acetylcholine