title: [Activating protein kinase C enhances ventricular action potential duration restitution and increase arrhythmia susceptibility in Langendorff-perfused rabbit hearts].
abstract: OBJECTIVE
  To determine effects of activating protein kinase C (PKC) on ventricular action potential duration restitution (APDR) and Burst stimulus induced arrhythmia in Langendorff-perfused rabbit hearts.
  
  
  METHODS
  Male rabbits were equally divided into three groups randomly: control group (Tyrode's solution perfusion), PKC agonist phorbol-12-myristate-13-acetate (PMA, 100 nmol/L) group and PKC inhibitor bisindolylmaleimide (BIM, 500 nmol/L) group. Thirty minutes after perfusion, the monophasic action potential (MAP) and effective refractory period (ERP) were determined in right basal ventricle (RB), right apex (RA), left basal ventricle (LB) and left apex (LA) of all the animals, and APDR curve was drawn. Burst stimulus method was used to induce ventricular arrhythmia in perfused rabbit hearts; Real-time PCR was used to detect the mRNA expression of PKC in four different areas of ventricle.
  
  
  RESULTS
  Compared with the control group, the ERP, 90% of monophasic action potential duration (MAPD(90)) and ERP/MAPD(90) were significantly shortened (all P < 0.01), the max slopes (S(max)) of APDR curve were significantly steeper (RB: 1.22 ± 0.23 vs. 0.65 ± 0.19; RA: 2.99 ± 0.29 vs. 1.02 ± 0.18; LB: 1.84 ± 0.21 vs. 0.85 ± 0.12; LA: 4.02 ± 0.32 vs.1.12 ± 0.23, all P < 0.01) and the incidences of ventricular arrhythmia were significantly increased in the PMA group. All parameters were similar between the BIM group and the control group (all P > 0.05).
  
  
  CONCLUSIONS
  Activating PKC could enhance the max slopes of APDR curve at various ventricular areas and subsequently increase arrhythmia susceptibility in Langendorff-perfused rabbit hearts.
authors.affiliation: Cardiovascular Research Institute, Wuhan University, Wuhan, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Mu
authors.initials: M
authors.lastname: Qin
authors.forename: He
authors.initials: H
authors.lastname: Hu
authors.forename: He
authors.initials: H
authors.lastname: Huang
authors.forename: Cong-xin
authors.initials: CX
authors.lastname: Huang
mesh_terms: D000200:Action Potentials; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology*; D008297:Male; D011493:Protein Kinase C / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D011493:Protein Kinase C