Elsevier

The Journal of Pain

Volume 6, Issue 1, January 2005, Pages 12-20
The Journal of Pain

Original reports
Selective contribution of Egr1 (zif/268) to persistent inflammatory pain

https://doi.org/10.1016/j.jpain.2004.10.001Get rights and content
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Abstract

The zinc finger transcription factor Egr1 is critical for coupling extracellular signals to changes in cellular gene expression. Expression of Egr1, as well as other immediate early genes, is up-regulated in response to a number of noxious stimuli. Activity-dependent activation of Egr1 has been reported in forebrain regions, including the anterior cingulate cortex (ACC), after peripheral injury. However, no study has reported a direct contribution of Egr1 to behavioral nociceptive responses. Here, we use Egr1 knockout mice to show that Egr1 is selectively required for behavioral responses to persistent inflammatory pain. Behavioral responses to peripheral inflammation were significantly reduced in Egr1 knockout mice, whereas responses to acute noxious stimuli were normal. In addition, inflammation triggered an up-regulation of Egr1 expression in the ACC of wild-type mice. Last, synaptic potentiation induced by theta (θ) burst stimulation in the ACC was significantly reduced or blocked in Egr1 knockout mice. Our study suggests that the transcription factor Egr1 plays a selective role in nociceptive behavioral responses to persistent inflammatory pain but not to acute noxious stimuli.

Perspective

Chronic pain diminishes the quality of life. Here, we show that the immediate early gene Egr1 plays a role in chronic inflammatory, but not acute, pain. Egr1 knockout mice showed reduced nociceptive behaviors to persistent inflammatory pain and inflammation increased Egr1 expression in the anterior cingulate cortex of wild-type mice.

Key words

Egr1
knockout mice
inflammatory pain
anterior cingulate cortex
long-term potentiation

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Supported by grants from the EJLB-CIHR Michael Smith Chair in Neurosciences and Mental Health, Canadian Research Chair, and NIH NINDS NS42722 to M. Z.