title: [Increased small conductance calcium-activated potassium channel (SK2 channel) current in atrial myocytes of patients with persistent atrial fibrillation].
abstract: OBJECTIVE
  To compare the amplitude of the SK2 current (small conductance calcium-activated potassium channel) in human atrial myocytes with or without persistent atrial fibrillation (AF).
  
  
  METHODS
  Right atrial appendage was obtained from 15 patients with sinus rate (SR) and 7 patients with AF underwent surgical valve replacement. Single myocyte was isolated by enzymatic dissociation method and the SK2 channel current density was recorded using whole-cell patch clamp techniques to detect the changes. Immunofluorescence was used to observe SK2 channel protein distribution on right atrial appendage.
  
  
  RESULTS
  Using the whole cell patch-clamp recording techniques, an inward rectifier K(+) mix currents could be obtained from both SR (n = 15) and AF (n = 7) samples, I(K1) mix currents density in single myocyte of AF group was significantly increased than in SR group [(-16.42 ± 5.32) pA/pF vs (-6.59 ± 2.24) pA/pF, P < 0.01], which could be partially inhibited by apamin (100 nmol/L). The apamin-sensitive current was obtained by subtraction of the currents before and after treatment with apamin. SK2 current density was significantly increased in AF group than that of SR group [(-9.81 ± 2.54) pA/pF vs (-3.67 ± 0.37) pA/pF, P < 0.01]. SK2 channel protein was evidenced with immunofluorescence method in right atrial appendage from AF group and SR group.
  
  
  CONCLUSIONS
  SK2 channel protein and current were present in atrial myocytes. The SK2 current density was significantly increased in AF group than in SR group suggesting that the increase of SK2 current might contribute to the electrical remodeling in AF patients.
authors.affiliation: Intitute of Myocardium Electrophysiology of Luzhou Medical College, Luzhou 646000, China.
authors.forename: Miao-ling
authors.initials: ML
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Ming
authors.initials: M
authors.lastname: Lei
authors.forename: Xiao-qiu
authors.initials: XQ
authors.lastname: Tan
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.forename: Tai-peng
authors.initials: TP
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Pei
authors.forename: Xiao-rong
authors.initials: XR
authors.lastname: Zeng
mesh_terms: D001030:Apamin / Q000494:pharmacology; D001281:Atrial Fibrillation / Q000378:metabolism*; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D008297:Male; D032383:Myocytes, Cardiac / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051640:Small-Conductance Calcium-Activated Potassium Channels / Q000187:drug effects / Q000378:metabolism*
chemical_list: D051640:Small-Conductance Calcium-Activated Potassium Channels; D001030:Apamin