Multiphasic morphine modulation of substance P release from capsaicin-sensitive primary afferent fibers.

Journal Article (Journal Article)

Morphine produces a multiphasic modulation of K+-evoked substance P release from trigeminal slices and dorsal root ganglion neurons in culture. We now found that the C-fiber stimulant, capsaicin (1 microM), evoked release of substance P that was inhibited, enhanced and inhibited by 0.1 nM, 1 microM, and 10 microM morphine, respectively. This morphine's multiphasic effect was blocked by naloxone (100 nM). Neonatal treatment with capsaicin produced thermal hypoalgesia and abolished the multiphasic effect of morphine on substance P release evoked by 50 mM K+. These findings suggest that the multiphasic modulation of substance P release by morphine is dependent on C-type afferents and may be of relevance to nociception.

Full Text

Duke Authors

Cited Authors

  • Cano, G; Arcaya, JL; Gómez, G; Maixner, W; Suarez-Roca, H

Published Date

  • October 1999

Published In

Volume / Issue

  • 24 / 10

Start / End Page

  • 1203 - 1207

PubMed ID

  • 10492514

Electronic International Standard Serial Number (EISSN)

  • 1573-6903

International Standard Serial Number (ISSN)

  • 0364-3190

Digital Object Identifier (DOI)

  • 10.1023/a:1020963120333


  • eng