title: [Composition of potassium channels in normal rat coronary smooth muscle cells and activation effects of docosahexaenoic acid].
abstract: OBJECTIVE
  To investigate the composition of potassium channels in normal rat coronary smooth muscle cells (CASMCs) and the activation effects of docosahexaenoic acid (DHA).
  
  
  METHODS
  CASMCs were isolated by enzyme digestion.Effects of different types of potassium channel blockers and/or DHA on potassium channels currents were studied by whole-cell patch clamp technique.
  
  
  RESULTS
  Potassium currents were significantly increased with 5 μmol/L DHA perfusion (P<0.05). The current density was increased from (52.80±6.68) pA/pF to (110.09±13.39) pA/pF (P<0.05) after DHA perfusion when the stimulation voltage was 100 mV.Compared with baseline, potassium currents were significantly decreased by various inhibitor perfusion (tetraethylammonium: (49.63±5.75) pA/pF vs. (13.96±2.18) pA/pF; ibritoxin: (50.67±7.89) pA/pF vs. (26.53±4.68) pA/pF; TRAM-34: (52.60±7.02) pA/pF vs. (46.05±7.60) pA/pF; apamin: (51.97±3.83) pA/pF vs. (44.89±5.04) pA/pF; 4-aminopyridine: (51.19±3.44) pA/pF vs. (29.92±2.81) pA/pF; glyburide: (49.67±1.77) pA/pF vs. (49.61±1.87) pA/pF, all P<0.05). In presence of different inhibitors, potassium channel current densities were increased after DHA perfusion except tetraethylammonium (tetraethylammonium: ( 12.79±1.89) pA/pF; ibritoxin: (67.08±5.54) pA/pF; TRAM-34: (117.91±21.79) pA/pF; apamin: (108.33±7.06) pA/pF; 4-aminopyridine: (127.73±20.56) pA/pF; glyburide: (121.53±13.83) pA/pF, all P<0.05 compared with baseline).
  
  
  CONCLUSIONS
  Large-conductance calcium-activated potassium channel and voltage-gated potassium channel are the major constituents of potassium channels in CASMCs.DHA can activate potassium channels in CASMCs, mainly the large conductance calcium-activated potassium channel, thus dilate coronary arteries.
authors.affiliation: Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi 214023, China.
authors.forename: L L
authors.initials: LL
authors.lastname: Qian
authors.forename: R X
authors.initials: RX
authors.lastname: Wang
authors.forename: M Q
authors.initials: MQ
authors.lastname: Sun
authors.forename: D Y
authors.initials: DY
authors.lastname: Xia
authors.forename: X
authors.initials: X
authors.lastname: Tang
authors.forename: Y
authors.initials: Y
authors.lastname: Ji
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.forename: X Y
authors.initials: XY
authors.lastname: Liu
authors.forename: S P
authors.initials: SP
authors.lastname: Dang
authors.forename: Q
authors.initials: Q
authors.lastname: Chai
authors.forename: T
authors.initials: T
authors.lastname: Lu
mesh_terms: D000818:Animals; D003331:Coronary Vessels / Q000166:cytology; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D051036:Large-Conductance Calcium-Activated Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D004281:Docosahexaenoic Acids