Kael M. Smith

Date of Graduation

Fall 2011

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Paul L. Durham

Abstract

Calcitonin gene-related peptide (CGRP), a neuropeptide released in response to trigeminal nerve activation, is implicated in migraine pathology. CGRP is thought to play an important role in the development of central sensitization, which involves increased neuron-glia interactions. The goal of this study was to utilize primary cultured brain stem and upper spinal cord tissue (C1/C2) to investigate CGRP-mediated release of 19 cytokines from glial cells implicated in central sensitization and pain. Under my growth conditions, all of the astrocytes and microglia express the CGRP receptor subunit protein RAMP1, which confers selectivity for CGRP and CGRP8-37. Treatment of primary glial cultures with 500 nM CGRP for 2 hours resulted in aa > 3-fold increase in the level of many of the cytokines as determined using a cytokine antibody array (RayBiotech) and densitometry analysis. The stimulatory effect of CGRP on cytokine release was suppressed by pretreatment with 5 µM of the peptide antagonist CGRP 8- 37. Pretreatment with KT 5720 (1 µM), a selective inhibitor of protein kinase A, suppressed the stimulatory effects of CGRP on many, but not all cytokines, to near baseline control levels. These data provide evidence that CGRP is likely to function via multiple pathways to increase the release of cytokines from spinal glia. Results from my study provide evidence that CGRP can directly increase the release of cytokines known to promote and sustain central sensitization. Furthermore, based on my findings, we propose that inhibition of CGRP-mediated activation of astrocytes and microglia would be beneficial in the treatment migraine and temporomandibular joint disorder.

Keywords

CGRP, central sensitization, glia, cytokines, RAMP1

Subject Categories

Biology

Copyright

© Kael M. Smith

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