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Effect of ethanol on action potential and ionic membrane currents in rat ventricular myocytes
Author(s) -
Bébarová M.,
Matejovič P.,
Pásek M.,
Ohlídalová D.,
Jansová D.,
Šimurdová M.,
Šimurda J.
Publication year - 2010
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2010.02162.x
Subject(s) - ethanol , chemistry , sodium , alcohol , biophysics , potassium , patch clamp , membrane potential , myocyte , calcium , ionic bonding , medicine , biochemistry , ion , biology , receptor , organic chemistry
Aim: 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 m m , 3.5‰), I to (170 m m , 7.8‰) and I Na (220 m m , 10.1‰). Conclusion: 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.