Inhibitory effect of nociceptin on [3H]-5-HT release from rat cerebral cortex slices
Article first published online: 29 JAN 2009
1999 British Pharmacological Society
British Journal of Pharmacology
Volume 128, Issue 1, pages 119–123, September 1999
How to Cite
Siniscalchi, A., Rodi, D., Beani, L. and Bianchi, C. (1999), Inhibitory effect of nociceptin on [3H]-5-HT release from rat cerebral cortex slices. British Journal of Pharmacology, 128: 119–123. doi: 10.1038/sj.bjp.0702793
- Issue published online: 29 JAN 2009
- Article first published online: 29 JAN 2009
- (Received April 19, 1999, Accepted June 22, 1999)
- ORL1 receptors;
- 5-HT release;
- cerebral cortex;
The effect of nociceptin (NC) on 5-hydroxytryptamine (5-HT) release was studied in rat cerebral cortex slices preincubated with [3H]-5-HT and electrically stimulated (3 Hz, for 2 min) at the 45th (St1) and the 75th (St2) min of superfusion.
NC (0.1–3 μM), present in the medium from the 70th min onward, concentration-dependently reduced electrically evoked [3H]-5-HT efflux (pEC50=6.54, Emax −54%). The inhibition was not antagonized by naloxone (1 μM) ruling out the involvement of opioid receptors.
Phe1ψ(CH2-NH2)Gly2]NC(1-13)NH2, which acts as an opioid-like receptor (ORL1) antagonist at the peripheral level, behaved as a partial agonist in cerebral cortex slices i.e. it inhibited [3H]-5-HT efflux when added before St2, however, when present in the medium throughout the whole experiment, [Phe1ψ(CH2-NH2)Gly2]NC(1-13)NH2 prevented the action of NC added at the 70th min.
The non-selective ORL1 receptor antagonist, naloxone benzoylhydrazone (3 μM), in the presence of 10 μM naloxone, did not modify the St2/St1 ratio but completely abolished the NC effect.
These findings demonstrate that NC inhibits 5-HT release from rat cerebral cortex slices via ORL1 receptors, suggesting its involvement in central processes mediated by 5-HT.
British Journal of Pharmacology (1999) 128, 119–123; doi:10.1038/sj.bjp.0702793