Effect of ethanol on guinea pig ventricular action potentials
| Autor: | Adriana Gallardo-Carpentier, Robert G. Carpentier |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Membrane potential
Ethanol Chemistry Guinea Pigs Catechols Action Potentials Heart Propranolol Resting potential Membrane Potentials Guinea pig Norepinephrine (medication) Norepinephrine chemistry.chemical_compound Anesthesia Biophysics medicine Animals Verapamil Repolarization Cardiology and Cardiovascular Medicine medicine.drug |
| Zdroj: | Journal of Electrocardiology. 14:333-339 |
| ISSN: | 0022-0736 |
| DOI: | 10.1016/s0022-0736(81)81005-9 |
| Popis: | Summary The effects of low concentrations of ethanol on transmembrane potentials of guinea pig ventricular muscle were analyzed. Papillary muscles were superfused with Tyrode solution in vitro at 30°C while driven at 60 min.−1 Transmembrane potentials were recorded by means of intracellular microelectrodes before, during and after a 15 min exposure to ethanol. Ethanol 2.5 mg/100 ml (0.55mM) did not affect transmembrane potentials. Ethanol 5 mg/100 ml enhanced the amplitude of the action potential (AAP) without affecting the membrane resting potential (MRP) and the maximum velocity of the upstroke (dV/dt). Ethanol 40 mg/100 ml also enhanced AAP without modifying MRP and dV/dt. Verapamil and propranolol blocked the augmenting effect of ethanol on AAP. Ethanol 40 mg/100 ml also enhanced the amplitude of responses restored by norepinephrine in fibers depolarized by high [K]0 to a level of resting potential at which the fast component of the upstroke was abolished. The enhancement of AAP was accompanied by a shift of the plateau to more positive values, but the duration of the action potential measured at 50% of repolarization was not affected. The results indicate that ethanol in low concentrations augments, through a catechol-mediated effect, the slow component of the upstroke of ventricular action potentials. |
| Databáze: | OpenAIRE |
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