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Author Notes:

Correspondence: Dr. Stephen Traynelis, Departmant of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322-3090; Tel: 404 727 0357; Fax: 404 727 0365; Email: strayne@emory.edu

Acknowledgments: The authors thank Robert McKeon for assistance with image analysis, Sudar Alagarsamy and John Hepler for assistance with analysis of phosphoinositide hydrolysis, and Anna Orr for critical comments on the manuscript.

Disclosures: The authors declare no competing financial interest.

Subjects:

Research Funding:

This work was supported by the NIH-NINDS NS039419 (SFT), NS053062 (CEH), NARSAD (SFT, GM), and PRIN 2007 (GM).

Keywords:

  • N-methyl-D-aspartate
  • glutamate
  • thrombin
  • protease activated receptor
  • PAR
  • ischemia
  • stroke
  • neuronal death
  • neuroprotection

Protease-activated receptor 1-dependent neuronal damage involves NMDA receptor function

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Journal Title:

Experimental Neurology

Volume:

Volume 217, Number 1

Publisher:

, Pages 136-146

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Protease-activated receptor 1 (PAR1) is a G-protein coupled receptor that is expressed throughout the central nervous system. PAR1 activation by brain-derived as well as blood-derived proteases has been shown to have variable and complex effects in a variety of animal models of neuronal injury and inflammation. In this study, we have evaluated the effects of PAR1 on lesion volume in wild-type or PAR1−/− C57Bl/6 mice subjected to transient occlusion of the middle cerebral artery or injected with NMDA in the striatum. We found that removal of PAR1 reduced infarct volume following transient focal ischemia to 57% of control. Removal of PAR1 or application of a PAR1 antagonist also reduced the neuronal injury associated with intrastriatal injection of NMDA to 60% of control. To explore whether NMDA receptor potentiation by PAR1 activation contributes to the harmful effects of PAR1, we investigated the effect of NMDA receptor antagonists on the neuroprotective phenotype of PAR1−/− mice. We found that MK801 reduced penumbral but not core neuronal injury in mice subjected to transient middle cerebral artery occlusion or intrastriatal NMDA injection. Lesion volumes in both models were not significantly different between PAR1−/− mice treated with and without MK801. Use of the NMDA receptor antagonist and dissociative anesthetic ketamine also renders NMDA-induced lesion volumes identical in PAR1−/− mice and wild-type mice. These data suggest that the ability of PAR1 activation to potentiate NMDA receptor function may underlie its harmful actions during injury.

Copyright information:

© 2009 Elsevier Inc. All rights reserved.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported License (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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