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J Cardiovasc Pharmacol. 2014 Aug;64(2):134-41. doi: 10.1097/FJC.0000000000000097.

Proarrhythmic effects of aldosterone during myocardial ischemia-reperfusion: implication of the sarcolemmal-KATP channels.

Author information

1
*Department of Cardiology, CHU de Caen, Caen, France; †Research Unit Signalisation, Électrophysiologie et Imagerie des Lésions d'Ischémie-Reperfusion Myocardique, Université de Caen Basse-Normandie, Caen, France; ‡Department of Cardiovascular Sciences, Sapienza University, Rome, Italy; and §Université de Caen Basse-Normandie, Medical School, Caen, France.

Abstract

OBJECTIVE:

To assess the electrophysiological impact of aldosterone during myocardial ischemia-reperfusion.

METHODS:

We used an in vitro model of "border zone" using rabbit right ventricle and standard microelectrodes.

RESULTS:

Aldosterone (10 and 100 nmol/L) shortened ischemic action potential [action potential duration at 90% of repolarization (APD90), from 55 ± 3 to 39 ± 1 ms and 36 ± 3 ms, respectively, P < 0.05] and induced resting membrane potential (RMP) hyperpolarization in the nonischemic zone (from -83 ± 1 to -93 ± 7 mV and -94 ± 3 mV, respectively, P < 0.05) and in the ischemic zone during reperfusion (from -81 ± 2 to -88 ± 2 mV and -91 ± 2 mV, respectively, P < 0.05). Bimakalim, an ATP-sensitive potassium (K(ATP)) channel opener, also induced RMP hyperpolarization and APD90 shortening. Aldosterone (10 and 100 nmol/L) increased APD90 dispersion between ischemic and nonischemic zones (from 96 ± 3 to 117 ± 5 ms and 131 ± 6 ms, respectively, P < 0.05) and reperfusion-induced severe premature ventricular contraction occurrence (from 18% to 67% and 75%, respectively, P < 0.05). Adding glibenclamide, a nonspecific K(ATP) antagonist, to aldosterone superfusion abolished these effects different to sodium 5-hydroxydecanoate, a mitochondrial-K(ATP) antagonist.

CONCLUSIONS:

In this in vitro rabbit model of border zone, aldosterone induced RMP hyperpolarization and decreased ischemic APD90 evoking the modulation of K currents. Glibenclamide prevented these effects different to 5-hydroxydecanoate, suggesting that sarcolemmal-K(ATP) channels may be involved in this context.

PMID:
24662493
DOI:
10.1097/FJC.0000000000000097
[Indexed for MEDLINE]

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