title: [Effect of GBE50 on delayed rectifier potassium current of ventricular myocytes in ischemic guinea pig].
abstract: OBJECTIVE
  Ginkgo biloba extract 50 (GBE50) is a new multicomponent drug with a polyvalent action extracted from the leave of Ginkgo biloba. The aim of this experiment was to study the effects of GBE50 on delayed rectifier potassium current (I(K)) in ventricular myocytes under normal and simulated ischemia conditions in guinea pigs.
  
  
  METHODS
  Single ventricular myocytes were isolated by an enzymatic dissociation method. I(K) were recorded by whole-cell patch clamp technique in voltage clamp mode. GBE50 was added to the perfusion chamber from low to high concentrations (25, 50,100 mg/L) in normal condition. Different concentrations of GBE50 (25, 50, 100 mg/L) were prepared with simulated ischemic fluid.
  
  
  RESULTS
  (1) Under normal condition, 100 mg/L GBE50 decreased I(K) (n = 7, P < 0.05). (2) Under ischemia condition, it was observed that I(K) was inhibited (n = 8, P < 0.05). (3) Perfusion with ischemia solution containing 50 mg/L (n = 8, P > 0.05) and 100 mg/L GBE50 (n = 6, P > 0.05) could reverse the decrease of I(K).
  
  
  CONCLUSIONS
  GBE50 significantly decreased I(K) in a concentration-dependent manner. GBE50 could alleviate the electrophysiological heterogeneity of myocardium to prevent ischemic myocardium from arrhythmia.
authors.affiliation: Department of Physiology, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Liu
authors.forename: Zhi-Xiong
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Xing-Yu
authors.initials: XY
authors.lastname: Wang
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D051668:Delayed Rectifier Potassium Channels / Q000187:drug effects*; D020441:Ginkgo biloba; D006168:Guinea Pigs; D017202:Myocardial Ischemia / Q000378:metabolism / Q000503:physiopathology*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010936:Plant Extracts / Q000494:pharmacology*; D000096983:Ginkgo Extract
chemical_list: D051668:Delayed Rectifier Potassium Channels; D010936:Plant Extracts; C583942:Ginkgo biloba extract 50; D000096983:Ginkgo Extract