title: Carbachol prolongs ventricular repolarisation through nitric oxide release in an intact heart.
abstract: OBJECTIVE
  The primary ain of this study was to investigate the effect of carbachol on ventricular repolarisation in an intact animal heart.
  
  
  METHODS
  In five sheep, carbachol was administered to the left circumflex coronary artery (LCX) at 1.0 and 2.5 micromol/ml/min respectively for 3 min. Multiple unipolar ECGs were acquired from the epicardium of LCX territory. Administration of carbachol at 2.5 micromol/ml/min was also repeated after pre-treatment with nitro-L-arginine (20 mg/kg), a nitric oxide synthase inhibitor.
  
  
  RESULTS
  Carbachol at 1.0 or 2.5 micromol/ml/min resulted in a T wave inversion and ARI prolongation in the LCX territory. The increase in ARI at 1.0 and 2.5 micromol/ml/min was 38 +/- 17 and 58 +/- 14 ms respectively (p<0.05). T wave inversion and ARI prolongation at 2.5 micromol/ml/min was diminished by pre-treatment with nitro-L-arginine.
  
  
  CONCLUSIONS
  Carbachol results in a dose-dependent prolongation in ventricular repolarisation in this open-chest animal model. This effect is partially mediated by endogenous nitric oxide.
authors.affiliation: School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia. lwang@csu.edu.au
authors.forename: Lexin
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D002217:Carbachol / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006321:Heart / Q000187:drug effects*; D008297:Male; D018721:Muscarinic Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D009206:Myocardium / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D019335:Nitroarginine / Q000494:pharmacology; D012756:Sheep; D017725:Ventricular Pressure / Q000187:drug effects* / Q000502:physiology
chemical_list: D004791:Enzyme Inhibitors; D018721:Muscarinic Agonists; D019335:Nitroarginine; D009569:Nitric Oxide; D002217:Carbachol