We have located links that may give you full text access.
Journal Article
Research Support, N.I.H., Extramural
Muscle inflammation induces a rapid increase in calcitonin gene-related peptide (CGRP) mRNA that temporally relates to CGRP immunoreactivity and nociceptive behavior.
Neuroscience 2006 December
Recent data support an important role for calcitonin gene-related peptide (CGRP) in deep tissue nociceptive processing. Using real-time reverse transcriptase polymerase chain reaction (RT-PCR), radioimmunoassay, immunohistochemistry and behavioral testing, we studied the early time course of CGRP mRNA and protein expression as well as nociceptive behavior following muscle inflammation. A rapid and significant increase in CGRP mRNA occurred in the mandibular division (V3) of the ipsilateral trigeminal ganglion at 30 minutes, 4 and 24 h after the injection of complete Freund's adjuvant as an inflammatory agent into rat masseter muscle. No change in mRNA occurred in the ipsilateral ophthalmic and maxillary divisions (V1/V2) or in the contralateral V3. The levels of immunoreactive calcitonin gene-related peptide (iCGRP) in the ipsilateral V3 significantly increased at 1, 4 and 24 h following muscle inflammation. In contrast, no change occurred in iCGRP levels in either the ipsilateral V1/V2 or contralateral V3. When saline was injected into the masseter muscle, the levels of mRNA or iCGRP did not change in the ipsilateral V3 suggesting that the biochemical changes are specific to CFA-induced muscle inflammation. The number of muscle afferent neurons immunoreactive for CGRP was significantly reduced compared with control at 1, 4 and 24 h in the ipsilateral but not in the contralateral trigeminal ganglion following inflammation. This decrease in the ipsilateral ganglion may indicate a loss of intrasomatic CGRP as a result of increased axonal transport away from the neuronal cell body and/or release of CGRP. Behavioral testing showed a reduction in head withdrawal thresholds bilaterally from 30 min through 24 h following muscle inflammation. Thus upregulation of CGRP mRNA and iCGRP levels are temporally related to the development of inflammation and lowered pain thresholds. The present data support the hypothesis that CGRP is upregulated during deep tissue inflammation and suggest that gene transcription is involved in this upregulation.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app