Activation of trigeminal nociceptive neurons by parotid PAR-2 activation in rats

Neuroreport. 2004 Jul 19;15(10):1617-21. doi: 10.1097/01.wnr.0000134991.97051.6b.

Abstract

To clarify involvement of protease-activated receptor-2 (PAR-2) in parotid pain, we examined whether PAR-2 activation in the parotid gland could activate trigeminal nociceptive neurons in anesthetized rats, by analyzing immunoreactive Fos as a nociceptive marker. Either the PAR-2 agonist SLIGRL-NH2 or capsaicin, injected into the parotid duct, caused expression of Fos in the trigeminal subnucleus caudalis, although the PAR-2-inactive reversed peptide had no such effect. The Fos expression caused by PAR-2 activation was inhibited by ablation of capsaicin-sensitive sensory neurons. Intraductal SLIGRL-NH2 did not increase vascular permeability in the parotid gland. Our data thus reveal that activation of PAR-2 in the parotid gland can cause activation of trigeminal nociceptive neurons via capsaicin-sensitive sensory nerves most probably by a non-inflammatory mechanism.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Capsaicin / pharmacology
  • Cell Count / methods
  • Drug Interactions
  • Functional Laterality
  • Immunohistochemistry / methods
  • In Vitro Techniques
  • Male
  • Medulla Oblongata / cytology
  • Neurons / drug effects*
  • Neurons / physiology
  • Nociceptors / metabolism
  • Oligopeptides / pharmacology*
  • Oncogene Proteins v-fos / metabolism
  • Parotid Gland / innervation
  • Parotid Gland / metabolism*
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Wistar
  • Receptor, PAR-1 / genetics
  • Receptor, PAR-1 / metabolism
  • Receptor, PAR-2 / antagonists & inhibitors
  • Receptor, PAR-2 / genetics
  • Receptor, PAR-2 / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Time Factors
  • Trigeminal Ganglion / cytology*

Substances

  • Oligopeptides
  • Oncogene Proteins v-fos
  • RNA, Messenger
  • Receptor, PAR-1
  • Receptor, PAR-2
  • seryl-leucyl-isoleucyl-glycyl--arginyl-leucinamide
  • Capsaicin