Effects of nicotine and ethanol on rat atrial membrane potentials

doi:10.1016/0741-8329(92)90016-4

Alcohol

Volume 9, Issue 2, March–April 1992, Pages 87-92

https://doi.org/10.1016/0741-8329(92)90016-4 Get rights and content

Abstract

The purpose of this research was to study the effects of nicotine and ethanol, alone and in combination, on cardiac membrane potentials (MP). Rat atrial preparations driven at 5 Hz were superfused with Tyrode's solution (37°C) while recording MP with intracellular microelectrodes. Nicotine concentrations below and including 6.2 × 10⁻⁵ M did not affect MP. Within 15 s, nicotine 3.1 × 10⁻³ M shortened the action potential duration (APD) and depressed the overshoot of the action potential (OS). This action was blocked by atropine. After 3 min, nicotine prolonged the APD and depressed V_max of phase O, OS and the amplitude of the action potential (AAP), without affecting the resting membrane potential (RMP). Nifedipine blocked the depression of the OS while tetraethylammonium chloride blocked the prolongation of the APD. Acute exposure to ethanol depressed OS and AAP and shortened APD, but it did not affect RMP or V_max of phase O. When nicotine and ethanol were administered simultaneously, the APD-prolonging effects of nicotine prevailed. The influence of chronic ethanol ingestion on the acute action of nicotine and/or ethanol was studied in rats pair-fed a liquid diet with (ER) or without (NR) ethanol (35% of total caloric intake) for 24 weeks. Chronic ethanol ingestion accentuated the depressant effect of nicotine 3.1 × 10⁻³ M on OS and AAP, but it did not modify the APD-prolonging action of nicotine. The same results were observed when ER and NR were exposed to nicotine and ethanol simultaneously.

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^☆: This research was done in partial fulfillment of the requirements for the Ph.D. Degree in Physiology and Biophysics.

¹: Dr. Carryl is currently a Research Associate in the Division of Medicine, USUHS, Bethesda, MD 20814.

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ArticleEffects of nicotine and ethanol on rat atrial membrane potentials☆

Abstract

Alcohol

J. Nutr.

J. Mol. Cell. Cardiol.

Eur. J. Pharmacol.

Alcohol

Jpn. J. Pharmacol.

Gen. Pharmacol.

Eur. J. Pharmacol.

Heart rate, carbon monoxide level after smoking high, low, and non-nicotine cigarettes

Ann. Intern. Med.

Nicotine and the action potential of cat ventricle

J. Pharmacol. Exp. Ther.

The relation between membrane potential, membrane currents and activation of contraction in ventricular myocardial fibers

J. Physiol. (Lond.)

Acute and chronic effects of ethanol on sinoatrial electrophysiology in the rat heart

J. Cardiovase. Pharmacol.

The electrocardiogram of alcoholic cardiomyopathy

Br. Heart J.

The action of ethanol upon the action potential and contraction of ventricular muscle

Recent Adv. Stud. Cardiol. Metab.

Comparisson of potassium currents in rabbit atrial and ventricular cells

J. Physiol. (Lond.)

Article
Effects of nicotine and ethanol on rat atrial membrane potentials☆