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Cardiovasc Res. 2004 Feb 15;61(3):610-9.

Ischemic preconditioning activates AMPK in a PKC-dependent manner and induces GLUT4 up-regulation in the late phase of cardioprotection.

Author information

1
Second Department of Internal Medicine, Sapporo Medical University School of Medicine, South-1 west-1, Chou-ku Sapparo 060-8543, Japan.

Abstract

OBJECTIVE:

The aim of this study was to determine the role of AMP-activated protein kinase (AMPK) and its link to protein kinase C (PKC) in the late phase of cardioprotection afforded by ischemic preconditioning (PC) against myocardial stunning.

METHODS AND RESULTS:

Rabbits were instrumented with a balloon occluder around a coronary artery and with a Doppler sensor to monitor the thickening fraction (TF). Conscious rabbits underwent five cycles of 5-min ischemia/5-min reperfusion (I/R) on 2 consecutive days (days 1 and 2). Reduction of TF after I/R was significantly less and recovery of TF was faster on day 2, indicating a late PC effect. PC provoked translocation of PKC- from the cytosol to the membrane and significantly increased AMPK activity by 100% immediately after PC. The mRNA level of GLUT4, a glucose transporter, was elevated by 150% at 3 h after PC, and the total protein level of GLUT4 was increased by 107% at 24 h after PC. The level of sarcolemmal GLUT4 protein after I/R on day 2 was 41% higher than its level after I/R on day 1. AMPK activation and up-regulation of GLUT4 by PC were abrogated by pre-treatment with PKC inhibitors.

CONCLUSION:

PC activated AMPK and up-regulated GLUT4 expression in a PKC-dependent manner. This GLUT4 up-regulation at 24 h after PC may contribute to attenuation of myocardial stunning.

PMID:
14962491
DOI:
10.1016/j.cardiores.2003.10.022
[Indexed for MEDLINE]

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