title: K(ATP)-mediated vasodilation is impaired in obese Zucker rats.
abstract: OBJECTIVE
  Skeletal muscle blood flow during exercise is impaired in obesity. We tested the hypothesis that the attenuated vasodilation in skeletal muscle arterioles of obese Zucker rats (OZR) is due to altered K(ATP) channel-mediated vasodilation.
  
  
  METHODS
  K(ATP) channel function was determined in isolated skeletal muscle arterioles in response to the K(ATP) opener cromakalim (0.1-10 microM) during normal myogenic tone and alpha-adrenergic-mediated tone (0.1 microM phenylephrine). The spinotrapezius muscle was prepared and the vasodilatory responses to muscle stimulation or iloprost (0.028-2.8 microM) were observed before and after the application of the K(ATP) inhibitor, glibenclamide (10 microM). Channel subunit expression was determined by using western blot analyses.
  
  
  RESULTS
  Cromakalim concentration-response curves were shifted in OZR as compared to lean controls. OZR exhibited impaired functional and iloprost-induced vasodilation as compared to the lean controls. Glibenclamide inhibited the functional and iloprost-induced dilation in the lean rats with no effects in the obese a nimals. Channel subunit expression was similar in femoral arteries.
  
  
  CONCLUSIONS
  The impaired functional vasodilation in the OZR is associated with altered K(ATP) channel sensitivity.
authors.affiliation: Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Hodnett
authors.forename: Lusha
authors.initials: L
authors.lastname: Xiang
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Dearman
authors.forename: Cory B
authors.initials: CB
authors.lastname: Carter
authors.forename: Robert L
authors.initials: RL
authors.lastname: Hester
mesh_terms: D000818:Animals; D001160:Arterioles / Q000378:metabolism / Q000503:physiopathology; D019806:Cromakalim / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005905:Glyburide / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D016285:Iloprost / Q000494:pharmacology; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism* / Q000503:physiopathology; D010656:Phenylephrine / Q000494:pharmacology; D015221:Potassium Channels / Q000096:biosynthesis*; D051381:Rats; D011924:Rats, Zucker; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D007004:Hypoglycemic Agents; D015221:Potassium Channels; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D019806:Cromakalim; D010656:Phenylephrine; D016285:Iloprost; D005905:Glyburide