title: Effects of ropivacaine on action potential configuration and ion currents in isolated canine ventricular cardiomyocytes.
abstract: BACKGROUND
  Despite the widespread clinical application of ropivacaine, there is little information on the cellular cardiac effects of the drug. In the current study, therefore, the concentration-dependent effects of ropivacaine on action potential morphology and the underlying ion currents were studied and compared with those of bupivacaine in isolated canine ventricular cardiomyocytes.
  
  
  METHODS
  Action potentials were recorded from the enzymatically dispersed cells using sharp microelectrodes. Conventional patch clamp and action potential voltage clamp arrangements were used to study the effects of ropivacaine on transmembrane ion currents.
  
  
  RESULTS
  Ropivacaine induced concentration- and frequency-dependent changes in action potential configuration, including shortening of the action potentials, reduction of their amplitude and maximum velocity of depolarization, suppression of early repolarization, and depression of plateau. Reduction in maximum velocity of depolarization was characterized with an EC50 value of 81 +/- 7 microm at 1 Hz. Qualitatively similar results were obtained with bupivacaine (EC50 = 47 +/- 3 microm). Under voltage clamp conditions, a variety of ion currents were blocked by ropivacaine: L-type calcium current (EC50 = 263 +/- 67 microm), transient outward current (EC50 = 384 +/- 75 microm), inward rectifier potassium current (EC50 = 372 +/- 35 microm), rapid delayed rectifier potassium current (EC50 = 303 +/- 47 microm), and slow delayed rectifier potassium current (EC50 = 106 +/- 18 microm).
  
  
  CONCLUSIONS
  Ropivacaine, similarly to bupivacaine, can modify cardiac action potentials and the underlying ion currents at concentrations higher than the usual therapeutic range. However, in cases of overdose, cardiac complications may be anticipated both during and after anesthesia due to the blockade of various ion currents.
authors: Department of Dentistry, University of Debrecen, Debrecen, Hungary.
authors: Adrienn
authors: A
authors: Szabó
authors: Norbert
authors: N
authors: Szentandrássy
authors: Péter
authors: P
authors: Birinyi
authors: Balázs
authors: B
authors: Horváth
authors: Gergely
authors: G
authors: Szabó
authors: Tamás
authors: T
authors: Bányász
authors: Ildikó
authors: I
authors: Márton
authors: János
authors: J
authors: Magyar
authors: Péter P
authors: PP
authors: Nánási
mesh_terms: D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000577:Amides / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects; D007473:Ion Channels / Q000502:physiology*; D017136:Ion Transport / Q000187:drug effects / Q000502:physiology; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000502:physiology; D000077212:Ropivacaine; D016276:Ventricular Function
chemical_list: D000577:Amides; D007473:Ion Channels; D000077212:Ropivacaine