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Brain-derived neurotrophic factor from microglia: a molecular substrate for neuropathic pain

Published online by Cambridge University Press:  22 May 2012

Tuan Trang ,
Simon Beggs  and
Michael W. Salter
Tuan Trang
Affiliation:
Program in Neurosciences and Mental Health, Hospital for Sick Children, Department of Physiology, University of Toronto and the University of Toronto Centre for the Study of Pain, Toronto, Ontario, Canada
Simon Beggs
Affiliation:
Program in Neurosciences and Mental Health, Hospital for Sick Children, Department of Physiology, University of Toronto and the University of Toronto Centre for the Study of Pain, Toronto, Ontario, Canada
Michael W. Salter*
Affiliation:
Program in Neurosciences and Mental Health, Hospital for Sick Children, Department of Physiology, University of Toronto and the University of Toronto Centre for the Study of Pain, Toronto, Ontario, Canada
*
Correspondence should be addressed to: Michael W. Salter, Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8Canada email: mike.salter@utoronto.ca
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Abstract

One of the most significant advances in pain research is the realization that neurons are not the only cell type involved in the etiology of chronic pain. This realization has caused a radical shift from the previous dogma that neuronal dysfunction alone accounts for pain pathologies to the current framework of thinking that takes into account all cell types within the central nervous system (CNS). This shift in thinking stems from growing evidence that glia can modulate the function and directly shape the cellular architecture of nociceptive networks in the CNS. Microglia, in particular, are increasingly recognized as active principal players that respond to changes in physiological homeostasis by extending their processes toward the site of neural damage, and by releasing specific factors that have profound consequences on neuronal function and that contribute to CNS pathologies caused by disease or injury. A key molecule that modulates microglia activity is ATP, an endogenous ligand of the P2 receptor family. Microglia expresses several P2 receptor subtypes, and of these the P2X4 receptor subtype has emerged as a core microglia–neuron signaling pathway: activation of this receptor drives the release of brain-derived neurotrophic factor (BDNF), a cellular substrate that causes disinhibition of pain-transmitting spinal lamina I neurons. Converging evidence points to BDNF from spinal microglia as being a critical microglia–neuron signaling molecule that gates aberrant nociceptive processing in the spinal cord. The present review highlights recent advances in our understanding of P2X4 receptor-mediated signaling and regulation of BDNF in microglia, as well as the implications for microglia–neuron interactions in the pathobiology of neuropathic pain.

Keywords

Microgliabrain-derived neurotrophic factorpurinoceptorsneuropathic painnerve injurychronic pain
Type
Reviews
Information
Neuron Glia Biology , Volume 7 , Special Issue 1: The Physiological Function of Microglia , February 2011 , pp. 99 - 108
Copyright
Copyright © Cambridge University Press 2012

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