Referenced in: none

Automatically associated channels: TRP , TRPV , TRPV1

Title: The antinociceptive potency of N-arachidonoyl-dopamine (NADA) and its interaction with endomorphin-1 at the spinal level.

Authors: Ibolya Farkas, Gábor Tuboly, György Benedek, Gyöngyi Horvath

Journal, date & volume: Pharmacol. Biochem. Behav., 2011 Oct , 99, 731-7

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/21624393

Abstract
The endogenous N-arachidonoyl-dopamine (NADA) activates both transient receptor potential vanilloid1 (TRPV1) and cannabinoid-1 (CB(1)) receptors. The goal of this study was to characterize the antinociceptive potential of NADA on inflammatory thermal hyperalgesia in rats at spinal level, and to determine its interaction with endomorphin-1 (EM) at the spinal level. The effects of NADA and EM on thermal hyperalgesia were evaluated in rats with a unilateral hind paw carrageenan-induced inflammation. Intrathecal injection of either EM (0.03-10 μg) or NADA (1.5-50 μg) caused dose-dependent antihyperalgesia, but NADA was 5.4 times less potent than EM. The antihyperalgesia caused by 15 μg NADA was inhibited by the TRPV1 antagonist AMG9810, but not by CB(1) antagonist/inverse agonist AM 251, whereas the effect of 50 μg NADA was decreased by both drugs. Co-administration of EM with NADA in 1:15 and 1:50 ratios produced a short-lasting potentiation, but isobolographic analysis for the whole investigated period revealed additive interaction between the two endogenous ligands. The results show that both TRPV1 and CB(1) receptor activation play a substantial role in the antinociceptive effects of NADA at spinal level, while co-administration of NADA with EM did not show potentiation.