title: Attenuation of conducted vasodilation in skeletal muscle arterioles during hyperhomocysteinemia.
abstract: BACKGROUND
  Vasomotor responses conducted from terminal arterioles to proximal vessels may contribute to match tissue demands and blood supply during skeletal muscle contraction. Conduction of vasodilatation (CVD) from distal resistance arterioles to the proximal arterioles and feeding arteries during metabolic demand is mediated by intercellular gap junctions in the vascular endothelium. The role of hyperhomocysteinemia (HHcy) in the musculoskeletal system during CVD is unclear. We hypothesize that during HHcy, there is impaired CVD due to decreased expression of endothelial-associated connexins and thus decreased tissue perfusion to the contracting skeletal muscles.
  
  
  METHODS
  CVD studies were performed in a gluteus maximus muscle preparation of wild-type (C57BL6/J) and CBS-/+ (HHcy) mice using intravital microscopy. Expression of connexins and myostatin protein (an antiskeletal muscle statin) was studied by Western blot and immunohistochemistry methods. Tissue perfusion to acetylcholine was assessed by the laser Doppler technique.
  
  
  RESULTS
  There was decreased CVD and tissue perfusion in response to acetylcholine in CBS-/+ mice compared to wild-type controls. There was decreased expression of connexins 37, 40 and 43 and increased expression of myostatin in CBS-/+ mice compared to wild-type controls.
  
  
  CONCLUSIONS
  Our findings suggest that CVD in skeletal muscle is decreased during HHcy due to decreased expression of gap junction connexins.
authors.affiliation: Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, Ky., USA. s0givv01@louisville.edu
authors.forename: S
authors.initials: S
authors.lastname: Givvimani
authors.forename: N
authors.initials: N
authors.lastname: Narayanan
authors.forename: F
authors.initials: F
authors.lastname: Armaghan
authors.forename: S
authors.initials: S
authors.lastname: Pushpakumar
authors.forename: S C
authors.initials: SC
authors.lastname: Tyagi
mesh_terms: D000818:Animals; D001160:Arterioles / Q000503:physiopathology*; D003094:Collagen / Q000378:metabolism; D017630:Connexins / Q000378:metabolism; D020138:Hyperhomocysteinemia / Q000378:metabolism / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism; D055435:Myostatin / Q000378:metabolism; D014664:Vasodilation
chemical_list: D017630:Connexins; C525912:Mstn protein, mouse; D055435:Myostatin; D003094:Collagen