Opposite modulation of capsaicin-evoked substance P release by glutamate receptors.

Journal Article (Journal Article)

Substance P and glutamate are present in primary afferent C-fibers and play important roles in persistent inflammatory and neuropathic pain. In the present study, we have examined whether activation of different glutamate receptor subtypes modulates the release of substance P evoked by the C-fiber selective stimulant capsaicin (1 microM) from rat trigeminal nucleus slices. The selective NMDA glutamate receptor agonist L-CCG-IV (1-10 microM) enhanced capsaicin-evoked substance P release about 100%. This facilitatory effect was blocked by 0.3 microM MK-801, a selective NMDA receptor antagonist. The metabotropic glutamate receptor agonists L-AP4 (group III) and DHPG (group I) (30-100 microM) inhibited capsaicin-evoked substance P release by approximately 60%. These inhibitory effects were blocked by the selective metabotropic glutamate receptor antagonist (+/-)-MCPG (5 microM). On the other hand, AMPA and kainate (0.1-10 microM), did not significantly affect capsaicin-evoked substance P release. Thus, substance P release from non-myelinated primary afferents, and possibly nociception, may be under the functional antagonistic control of some metabotropic and ionotropic glutamate receptor subtypes.

Full Text

Duke Authors

Cited Authors

  • Cuesta, MC; Arcaya, JL; Cano, G; Sanchez, L; Maixner, W; Suarez-Roca, H

Published Date

  • December 1999

Published In

Volume / Issue

  • 35 / 6

Start / End Page

  • 471 - 478

PubMed ID

  • 10524715

Electronic International Standard Serial Number (EISSN)

  • 1872-9754

International Standard Serial Number (ISSN)

  • 0197-0186

Digital Object Identifier (DOI)

  • 10.1016/s0197-0186(99)00081-9


  • eng