title: [Effects of docosahexaenoic acid on ion channels of rat coronary artery smooth muscle cells].
abstract: OBJECTIVE
  To investigate the effects of docosahexaenoic acid (DHA) on large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels and voltage-dependent K(+) (K(V)) channels in rat coronary artery smooth muscle cells (CASMCs), and evaluate the vasorelaxation mechanisms of DHA.
  
  
  METHODS
  BK(Ca) and K(V) currents in individual CASMC were recorded by patch-clamp technique in whole-cell configuration. Effects of DHA at various concentrations (0, 10, 20, 40, 60 and 80 µmol/L) on BK(Ca) and K(V) channels were observed.
  
  
  RESULTS
  (1) DHA enhanced IBK(Ca) and BK(Ca) tail currents in a concentration-dependent manner while did not affect the stably activated curves of IBK(Ca). IBK(Ca) current densities were (68.2 ± 22.8), (72.4 ± 24.5), (120.4 ± 37.9), (237.5 ± 53.2), (323.6 ± 74.8) and (370.6 ± 88.2)pA/pF respectively (P < 0.05, n = 30) with the addition of 0, 10, 20, 40, 60 and 80 µmol/L DHA concentration, and half-effect concentration (EC(50)) of DHA was (36.22 ± 2.17)µmol/L. (2) IK(V) and K(V) tail currents were gradually reduced, stably activated curves of IK(V) were shift to the right, and stably inactivated curves were shifted to the left in the presence of DHA. IK(V) current densities were (43.9 ± 2.3), (43.8 ± 2.3), (42.9 ± 2.0), (32.3 ± 1.9), (11.7 ± 1.5) and (9.6 ± 1.2)pA/pF respectively(P < 0.05, n = 30)post treatment with 0, 10, 20, 40, 60 and 80 µmol/L DHA under manding potential equal to +50 mV, and EC(50) of DHA was (44.19 ± 0.63)µmol/L.
  
  
  CONCLUSIONS
  DHA can activate BK(Ca) channels and block K(V) channels in rat CASMCs, the combined effects on BK(Ca) and K(V) channels lead to the vasodilation effects of DHA on vascular smooth muscle cells.
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Henan University of Science and Technology, Luoyang, China. dongpingshuan@163.com
authors.forename: Ping-shuan
authors.initials: PS
authors.lastname: Dong
authors.forename: Li-hong
authors.initials: LH
authors.lastname: Lai
authors.forename: Hong-lei
authors.initials: HL
authors.lastname: Wang
authors.forename: Shi-ying
authors.initials: SY
authors.lastname: Xing
authors.forename: Ji-hong
authors.initials: JH
authors.lastname: Zhu
authors.forename: Xu-ming
authors.initials: XM
authors.lastname: Yang
authors.forename: Shao-xin
authors.initials: SX
authors.lastname: Wang
authors.forename: Zhuan-zhen
authors.initials: ZZ
authors.lastname: Li
authors.forename: Xi-yan
authors.initials: XY
authors.lastname: Shang
mesh_terms: D000818:Animals; D003331:Coronary Vessels / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D005260:Female; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D051036:Large-Conductance Calcium-Activated Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D004281:Docosahexaenoic Acids