title: Effect of ethanol on action potential and ionic membrane currents in rat ventricular myocytes.
abstract: OBJECTIVE
  Even though alcohol intoxication is often linked to arrhythmias, data describing ethanol effect on cardiac ionic channels are rare. In addition, ethanol is used as a solvent of hydrophobic compounds in experimental studies. We investigated changes of the action potential (AP) configuration and main ionic membrane currents in rat cardiomyocytes under 20-1500 m(M) ethanol.
  
  
  METHODS
  Experiments were performed on enzymatically isolated rat right ventricular myocytes using the whole cell patch-clamp technique at room temperature.
  
  
  RESULTS
  Ethanol reversibly decelerated the upstroke velocity and decreased AP amplitude and duration at 0.2 and 3 Hz. The fast sodium current I(Na) , l-type calcium current I(Ca) and transient outward potassium current I(to) were reversibly inhibited in a concentration-dependent manner (50% inhibition at 446 ± 12, 553 ± 49 and 1954 ± 234 m(M), respectively, with corresponding Hill coefficients 3.1 ± 0.3, 1.1 ± 0.2 and 0.9 ± 0.1). Suppression of I(Na) and I(Ca) magnitude was slightly voltage dependent. The effect on I(Ca) and I(to) was manifested mainly as an acceleration of their apparent inactivations with a decreased slow and fast time constant respectively. As a consequence of marked differences in n(H) , sensitivity of the currents to ethanol at 10% inhibition decreases in the following order: I(Ca) (75 mm, 3.5‰), I(to) (170 m(M), 7.8‰) and I(Na) (220 m(M), 10.1‰).
  
  
  CONCLUSIONS
  Our results suggest a slight inhibition of all the currents at ethanol concentrations relevant to deep alcohol intoxication. The concentration dependence measured over a wide range may serve as a guideline when using ethanol as a solvent.
authors.affiliation: Department of Physiology, Masaryk University, Brno - Bohunice, Czech Republic. bebarova.lfmu@centrum.cz
authors.forename: M
authors.initials: M
authors.lastname: Bébarová
authors.forename: P
authors.initials: P
authors.lastname: Matejovič
authors.forename: M
authors.initials: M
authors.lastname: Pásek
authors.forename: D
authors.initials: D
authors.lastname: Ohlídalová
authors.forename: D
authors.initials: D
authors.lastname: Jansová
authors.forename: M
authors.initials: M
authors.lastname: Simurdová
authors.forename: J
authors.initials: J
authors.lastname: Simurda
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002492:Central Nervous System Depressants / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D006352:Heart Ventricles / Q000166:cytology*; D015640:Ion Channel Gating / Q000187:drug effects; D007473:Ion Channels / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism; D012997:Solvents
chemical_list: D002492:Central Nervous System Depressants; D007473:Ion Channels; D012997:Solvents; D000431:Ethanol; D012964:Sodium; D011188:Potassium; D002118:Calcium