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Mol Med. 2010 Jul-Aug;16(7-8):322-32. doi: 10.2119/molmed.2010.00006. Epub 2010 Apr 9.

Thrombin and its receptor enhance ST-segment elevation in acute myocardial infarction by activating the KATP channel.

Author information

1
Division of Cardiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.

Abstract

ST-segment elevation is the major clinical criterion for committing patients with chest pain to have emergent coronary revascularizations; however, the mechanism responsible for ST-segment elevation is unknown. In a guinea pig model of ST-segment elevation acute myocardial infarction (AMI), local application of hirudin, a thrombin antagonist, significantly decreased AMI-induced ST-segment elevation in a dose-dependent manner. Hirudin-induced (5 antithrombin units [ATU]) decrease in ST elevation was reversed by 250 nmol/L thrombin receptor activator peptide (TRAP). TRAP (250 nmol/L [100 microL]) significantly induced ST-segment elevation in hearts without AMI. The TRAP effect was blocked by 4 mg/kg glibenclamide and 4 mg/kg HMR1098 and partially blocked by 3 mg/kg 5HD. Pinacidil (0.45 mg/kg) simulated the effect of TRAP (250 nmol/L [100 microL]) on hearts without AMI. Moreover, single-channel recordings showed that TRAP induced ATP-sensitive K+ channel (KATP channel) activity, and this effect was blocked by HMR1098 but not 5HD. Finally, TRAP significantly shortened the monophasic action potential (MAP) at 90% repolarization (MAP90) and epicardial MAP (EpiMAP) duration. These effects of TRAP were completely reversed by HMR1098 and partially reversed by 5HD. Thrombin and its receptor activation enhanced ST-segment elevation in an AMI model by activating the sarcolemmal KATP channel.

PMID:
20386871
PMCID:
PMC2896465
DOI:
10.2119/molmed.2010.00006
[Indexed for MEDLINE]
Free PMC Article

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