Paper Information

Title: 

THE ROLE OF K-ATP CHANNEL IN THE PRECONDITIONING EFFECT OF MAGNESIUM IN THE RAT ISOLATED HEART

Type: POSTER
Author(s): BAZARGAN M.,FAGHIHI M.,KARIMIAN S.M.,CHITSAZ M.,MIRERSHADI F.
 
 
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2007Volume 18
 
 
Abstract: 

Background: There is growing interest for beneficial effect of Mg in the cardiovascular disorders. A number of cardiovascular disorders including myocardial infarction, arrhythmias and congestive heart failure have been associated with low extra cellular or intracellular concentrations of Mg. The aim of present study was to investigate the effects of magnesium (Mg) on cardiac function and infarct size in the globally ischemic-reperfusion in isolated rat heart. The mechanism of Mg-mediated cardioprotection was explored by combined use of Mg and a K-ATP channel opener, diazoxide and blocker, Glibenclamid (Gli).
Methods: Rat hearts were Langendorff-perfused, subjected to 30 minutes of global ischemia and 90 minutes of reperfusion, and assigned to one of the following treatment groups with 7 hearts in each group: (1) control, (2) ischemic-reperfusion, (IR), (3) ischemic preconditioning (IPC); or pretreatment with (4) 30 µmol/L Dia, (5) 8mmol/L magnesium, (6) 10 µmol/L Gli, (7) magnesium and Dia and (8) magnesium and Gli. Infarct size was measured by the triphenyltetrazolium chloride method. Left ventricular function was assessed by left ventricular developed pressure (LVDP), heart rate and coronary flow (CF).
Results: Mg limited infarct size (9.76 %vs 44.47% in IR, P<0.001) as did Dia (10.2
%vs 44.4% P<0.001) and IPC (8.69 %vs 44.47% in IR, P<0.001). The protective effect of magnesium was abolished by Gli (29.1%).
Conclusions: The administration of Mg had an anti-infarct effect in ischemic-reperfusion isolated rat hearts and improved cardiac function. These effects of Mg was not enhanced by the simultaneous administration of Mg and Dia, but abolished by coadminstration with Gli. Blockade of K-ATP channel abolished the protective effects of magnesium and suggest that K-ATP channel has an important role in this effects.

 
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