Intrinsic regulation of CGRP release by dental pulp sympathetic fibers

K. M. Hargreaves, W. R. Bowles, D. L. Jackson

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Neurotransmission from sympathetic and peptidergic afferent fibers participates in the regulation of pulpal blood flow (PBF) via opposing effects. In this study, we directly tested the hypothesis that activation of pulpal sympathetic terminals inhibits exocytosis of immunoreactive calcitonin gene-related peptide (iCGRP) from peptidergic afferents innervating bovine dental pulp. The results demonstrate that norepinephrine inhibits capsaicin-evoked iCGRP release. The application of α-adrenergic antagonists (phentolamine or phenoxybenzamine) increased spontaneous release of iCGRP. Moreover, administration of agents that evoke the release of sympathetic neurotransmitters (guanethidine or reserpine) inhibited capsaicin-evoked iCGRP release. Collectively, these results indicate that sympathetic neurotransmission inhibits exocytosis from pulpal peptidergic afferent fibers. Analysis of these data supports the hypothesis that peripheral sympathetic vasomotor control may operate by a direct mechanism (vasoconstriction) as well as by an indirect mechanism (e.g., inhibition of exocytosis from afferent fibers). Since capsaicin-sensitive neurons are nociceptors, it is possible that certain sympathetic neurotransmission may modulate pain.

Original languageEnglish (US)
Pages (from-to)398-401
Number of pages4
JournalJournal of dental research
Issue number5
StatePublished - May 2003


  • CGRP
  • Capsaicin
  • Dental pulp
  • Sympathetic


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