title: Oleic acid inhibits the K(ATP) channel subunit Kir6.1 and the K(ATP) current in human umbilical artery smooth muscle cells.
abstract: BACKGROUND
  The objective of the present study was to determine the effect of various concentrations of oleic acid (OA) on KATP channel expression and the potential relationship to exogenous nitrogen monoxide and protein kinase C levels.
  
  
  METHODS
  Human umbilical artery smooth muscle cells (HUASMCs), between the 7th and 10th passages, were divided into control group, OA group (final OA concentration of 0, 50, 100 or 200 μmol/L), nitric oxide (NO) intervention group, protein kinase C inhibitor group or GF-109203X (GFX) intervention group. Western immunoblotting was used to detect the protein expression of the KATP channel subunit Kir6.1. Also, quantitative real-time polymerase chain reaction analysis to determine Kir6.1 messenger RNA levels and whole-cell patch clamping to measure KATP currents were performed.
  
  
  RESULTS
  The results suggested that OA inhibited Kir6.1 protein and messenger RNA expression in HUASMCs. Under a high concentration of potassium (140 mmol/L), 100 μmol/L OA significantly reduced ATP-sensitive potassium current density, whereas a low extracellular concentration of potassium (5.4 mmol/L) did not influence KATP density. Pretreatment with either exogenous NO or GFX weakened the OA-induced inhibition of KATP in HUASMCs.
  
  
  CONCLUSIONS
  The study demonstrated that OA inhibited Kir6.1, a KATP channel subunit, in HUASMCs, and indirectly inhibited the KATP current. In addition, the results indicated that NO and/or GFX partially reversed OA inhibition in HUASMCs.
authors.affiliation: Department of Cardiovascular Medicine, the First Affiliated Hospital of the Xi'an Jiaotong University School of Medicine, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, China.
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Bai
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Tian
authors.forename: Ting-Zhong
authors.initials: TZ
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Du
authors.forename: Yu-Tao
authors.initials: YT
authors.lastname: Xi
authors.forename: Yue
authors.initials: Y
authors.lastname: Wu
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Ai-Qun
authors.initials: AQ
authors.lastname: Ma
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D054086:KATP Channels / Q000502:physiology*; D008301:Maleimides / Q000494:pharmacology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000494:pharmacology; D019301:Oleic Acid / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D014469:Umbilical Arteries / Q000166:cytology
chemical_list: D007211:Indoles; D054086:KATP Channels; D008301:Maleimides; D012333:RNA, Messenger; C092520:uK-ATP-1 potassium channel; D012710:Serum Albumin, Bovine; D019301:Oleic Acid; D009569:Nitric Oxide; D011493:Protein Kinase C; C070515:bisindolylmaleimide I