PMID: 9554734Apr 29, 1998Paper

Differential role of epicardial and endocardial K(ATP) channels in potassium accumulation during regional ischemia induced by embolization of a coronary artery with latex

Journal of Cardiovascular Electrophysiology
S MiyoshiS Ogawa

Abstract

K(ATP) channels are activated predominantly in the epicardium during regional ischemia. Therefore, the role of K(ATP) channels in ischemia-induced rise of extracellular potassium concentration ([K+]o) might be greater in the epicardium. In 18 anesthetized dogs, the left anterior descending coronary artery (LAD) was ligated, followed by injection of 23-microm latex beads into the occluded artery to interrupt collateral flow, by which accumulated [K+]o might wash out. Epicardial and endocardial [K+]o were measured during a 20-minute period of ischemia using a valinomycin membrane. The dogs were divided into three groups: 6 control dogs (CTRL); 7 dogs pretreated with intravenous glibenclamide (0.3 mg/kg [GLIB]), a blocker of K(ATP) channels; and 5 dogs pretreated with intravenous nicorandil (0.2 to 0.25 mg/kg [NCR]), a K(ATP) channel opener. Before LAD occlusion, there was no difference in [K+]o among the three groups. In the control group, epicardial and endocardial [K+]o were increased to a similar level as a function of time after occlusion (CTRL) at both layers. Ischemia-induced epicardial [K+]o rise was suppressed by GLIB (8.4+/-0.4 vs 6.7+/-0.5 mM, P < 0.05) but augmented by NCR (12.9+/-2.0 mM, P < 0.05). In contrast, endoca...Continue Reading

References

Nov 1, 1981·Journal of Pharmacological Methods·D C WarltierH L Brooks

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Citations

Apr 3, 2012·American Journal of Physiology. Heart and Circulatory Physiology·Tyson G TaylorAlexey V Zaitsev
Sep 21, 2005·Heart Rhythm : the Official Journal of the Heart Rhythm Society·Ziad F IssaDouglas P Zipes
Oct 8, 2011·Circulation Research·Talha A FaridKumaraswamy Nanthakumar
Oct 13, 2009·American Journal of Physiology. Heart and Circulatory Physiology·Stéphane MasséKumaraswamy Nanthakumar
Jul 23, 2013·American Journal of Physiology. Heart and Circulatory Physiology·Tyson G TaylorAlexey V Zaitsev
Oct 9, 2007·American Journal of Physiology. Heart and Circulatory Physiology·Junichi ShimokawaHiroyuki Tsutsui

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