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
Language
- eng