The use of an in vivo model to study the effects of hyperhomocysteinaemia on vascular function.
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.
Hansrani
Monica
M
Northern Vascular Unit, Freeman Hospital, Newcastle upon Tyne, United Kingdom.
Stansby
Gerard
G
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
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; D005492:Folic Acid; D008715:Methionine; D000109:Acetylcholine