Elsevier

Brain Research

Volume 834, Issues 1–2, 10 July 1999, Pages 200-206
Brain Research

Short communication
The effects of RB101, a mixed inhibitor of enkephalin-catabolizing enzymes, on carrageenin-induced spinal c-Fos expression are completely blocked by β-funaltrexamine, a selective μ-opioid receptor antagonist

https://doi.org/10.1016/S0006-8993(99)01569-3Get rights and content

Abstract

We have demonstrated that pre-administered RB101 (40 mg/kg, i.v.), a mixed inhibitor of enkephalin-catabolizing enzymes, decreased spinal c-Fos expression induced 1 h and 30 min after intraplantar (i.pl.) carrageenin (41% reduction, p<0.01). These effects were completely blocked by pre-administered β-funaltrexamine (10 mg/kg, i.v., 24 h prior to stimulation), a selective long-lasting μ-opioid receptor antagonist. In conclusion, these results clearly demonstrate that the effects of endogenous enkephalins on noxiously evoked spinal c-Fos expression are essentially mediated via μ-opioid receptors.

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Acknowledgements

We thank R. Rambur for photographs. This work was supported by the Ministère de l'Education Nationale, de la Recherche et de la Technologie, the European Biomed program (Project B.M.H.4-CT95-0172), and the Association pour la Recherche sur le Cancer (ARC No. 9605).

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