title: Effects of amiloride on potassium and calcium currents in guinea pig ventricular myocytes.
abstract: OBJECTIVE
  To elucidate the possible mechanisms underlying antiarrhythmia of the non-selective Na+/H+ exchanger inhibitor--amiloride.
  
  
  METHODS
  Single ventricular cells were isolated using a double-enzyme method. Effects of amiloride on voltage-dependent potassium and calcium currents in isolated guinea pig ventricular myocyte were recorded by using whole-cell patch clamp techniques.
  
  
  RESULTS
  Exposure to amiloride (10 -100 micromol x L(-1)), the L-type and T-type calcium currents were depressed. Amiloride resulted in a concentration-dependent inhibition of peak (Ca,L), But amiloride did not change the shape of their I - V curves. It only decreased the amplitudes of the currents of the two types. When myocytes were incubated with 100 micromol x L(-1) amiloride, I(Kr) was slightly depressed and I(Ks) did not change. Amiloride (1 - 100 micromol x L(-10) depressed I(K1) in a concentration-dependent manner.
  
  
  CONCLUSIONS
  Amiloride depressed potassium and calcium currents, which may give support to its uses in some diseases of the cardiovascular system.
authors.affiliation: Department of Pharmacology, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China. chenglan1@hotmail.com
authors.forename: Lan
authors.initials: L
authors.lastname: Cheng
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Hong-Yi
authors.initials: HY
authors.lastname: Zhou
authors.forename: Wei-Xing
authors.initials: WX
authors.lastname: Yao
authors.forename: Guo-Jin
authors.initials: GJ
authors.lastname: Xia
authors.forename: Ming-Xing
authors.initials: MX
authors.lastname: Jiang
mesh_terms: D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000187:drug effects*; D020747:Calcium Channels, T-Type / Q000187:drug effects*; D002469:Cell Separation; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D024661:Potassium Channels, Inwardly Rectifying / Q000187:drug effects*; D024642:Potassium Channels, Voltage-Gated / Q000187:drug effects; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors
chemical_list: D000889:Anti-Arrhythmia Agents; D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated; D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1; D000584:Amiloride