title: Vascular function of the mesenteric artery isolated from thyroid hormone receptor-α knockout mice.
abstract: OBJECTIVE
  This study evaluated the consequences of thyroid hormone receptor-α (TRα) disruption on vascular reactivity.
  
  
  METHODS
  The activity of superior mesenteric arteries isolated from TRα knockout mice generated in the SV129 background (TRα(0/0)SV) or in a pure C57BL/6 background (TRα(0/0)C57) was compared to that of their corresponding wild-type strains (SV129 or C57BL/6 mice).
  
  
  RESULTS
  The wild-type SV129 mice exhibited an impaired acetylcholine (Ach)-induced mesenteric artery relaxation compared to C57BL/6 mice, associated with greater responses to angiotensin II (AII) and phenylephrine (PE). The disruption of TRα decreased the vascular response to sodium nitroprusside and PE in both the SV129 and C57BL/6 genetic backgrounds. Responses to Ach and AII were also blunted, but only in TRα(0/0)C57 mice. The administration of 3,3'5-triiodo-L-thyronine sodium salt (T3) elicited a vasodilatation in C57BL/6 mice even at the lowest concentration (10(-9)M); a maximal relaxation of more than 50% was observed with the concentrations between 10(-9) and 10(-8)M. However, the response to T3 was nearly absent in TRα(0/0)C57 mice.
  
  
  CONCLUSIONS
  TRα is essential for the control of vascular tone, particularly in thyroid hormone-mediated relaxation. The difference in response to Ach observed between the two wild-type mice should be taken into account for interpreting the vascular responses of genetically engineered mice.
authors.affiliation: Unit of Neurocardiology, EA 4612, Institute of Pharmaceutical and Biological Sciences, University Claude Bernard Lyon 1, Lyon, France.
authors.forename: Kiao Ling
authors.initials: KL
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Lo
authors.forename: Laurence
authors.initials: L
authors.lastname: Canaple
authors.forename: Karine
authors.initials: K
authors.lastname: Gauthier
authors.forename: Peggy
authors.initials: P
authors.lastname: Del Carmine
authors.forename: Michel
authors.initials: M
authors.lastname: Beylot
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005838:Genotype; D008297:Male; D017538:Mesenteric Artery, Superior / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010641:Phenotype; D013045:Species Specificity; D037021:Thyroid Hormone Receptors alpha / Q000819:agonists / Q000172:deficiency* / Q000235:genetics; D014284:Triiodothyronine / Q000494:pharmacology; D014661:Vasoconstriction; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D037021:Thyroid Hormone Receptors alpha; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D014284:Triiodothyronine