title: [Effect of antiarrhythmic peptide on ventricular arrhythmia induced by lysophosphatidic acid].
abstract: OBJECTIVE
  To investigate the effect and potential mechanism of lysophosphatidic acid (LPA) and antiarrhythmic peptide (AAP10) on rabbit ventricular arrhythmia.
  
  
  METHODS
  Twenty-four rabbits were randomly divided into three groups (n = 8 each): control group, LPA group and AAP10 + LPA group. Using arterially perfused rabbit ventricular wedge preparations, transmural ECG and action potentials from both endocardium and epicardium were simultaneously recorded in the whole process of all experiments with two separate floating microeletrodes. The incidence of ventricular arrhythmia post S1S2 stimulation was recorded. Protein levels of nonphosphorylated Cx43 and total Cx43 were evaluated by Western blot. The distribution of nonphosphorylated Cx43 was observed by confocal immunofluorescence microscopy.
  
  
  RESULTS
  Compared with the control group, the QT interval, endocardial action potential duration, transmural repolarization dispersion (TDR) and incidence of ventricular arrhythmia were significantly increased and nonphosphorylated Cx43 expression was significantly upregulated in the LPA group. Compared with the LPA group, cotreatment with AAP10 can reduce the QT interval, endocardial action potential duration, TDR and incidence of ventricular arrhythmia (25.0% vs 62.5%, P < 0.01) and downregulate nonphosphorylated Cx43.
  
  
  CONCLUSIONS
  LPA could promote the arrhythmia possibly by upregulating nonphosphorylated Cx43 and subsequent gap junction transmission inhibition. Gap junction enhancer AAP10 could attenuate the pro-arrhythmic effect of LPA probably by downregulating myocardial nonphosphorylated Cx43 expression.
authors.affiliation: Department of Heart Internal Medicine, Xiangfan Central Hospital, Xiangfan 441021, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.forename: Tian-jie
authors.initials: TJ
authors.lastname: Wang
authors.forename: Cun-tai
authors.initials: CT
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Ruan
authors.forename: Lian-dong
authors.initials: LD
authors.lastname: Li
authors.forename: Ren-de
authors.initials: RD
authors.lastname: Xu
authors.forename: Xiao-qing
authors.initials: XQ
authors.lastname: Quan
authors.forename: Ming-ke
authors.initials: MK
authors.lastname: Ni
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D018031:Connexin 43 / Q000378:metabolism; D008246:Lysophospholipids / Q000009:adverse effects*; D009842:Oligopeptides / Q000494:pharmacology*; D011817:Rabbits
chemical_list: C090806:AAP 10; D000889:Anti-Arrhythmia Agents; D018031:Connexin 43; D008246:Lysophospholipids; D009842:Oligopeptides; C032881:lysophosphatidic acid