JTC-801

447, 96

Male ICR (CD-1) subjected to nociceptin-induced allodynia test or hot plate test, and Male SD rats subjected to formalin-induced paw-licking response

Suspended in 0.5% methyl cellulose solution or dissolved in 5% sorbitol

JTC-801 displays about 12.5-, 129-, and 1055-fold selectivity for ORL1 receptor (Ki = 8.2 nM) over u-, kappa-, and delta-opioid receptors, respectively. JTC-801 does not inhibit forskolin-stimulated cyclic AMP accumulation in human ORL1 receptor-expressing HeLa cells, but it prevents nociceptin-induced inhibition of cyclic AMP accumulation, indicating that JTC-801 possesses full antagonistic activity. [2] In rat cerebrocortical membrane, JTC-801 inhibits ORL1 receptor with IC50 of 472 nM and u-receptor with IC50 of 1831 nM. JTC-801 completely antagonizes the suppression of nociceptin on forskolin-induced accumulation of cyclic AMP with IC50 of 2.58 uM in HeLa cells expressing ORL1 receptor. [1]

Human ORL1 receptor binding affinity, Human ORL1 receptor expressed in HeLa cells are harvested and homogenized in 50 mM Tris buffer (pH 7.4) containing 1 mM EDTA. After centrifugation for 30 minutes at 40, 000g, the pellets are resuspended in buffer containing 50 mM Tris, supplemented with 10 mM MgCl2 and 2 mM EGTA, and used as membrane preparations. 50 mM Tris (pH 7.4) supplemented with 2 mM EDTA and 0.1 mM (p-amidoinophenyl) methanesulphonyl fluoride hydrochloride containing 0.2% bovine serum albumin is used for the binding buffer. For saturation binding assay, the cell membrane preparations are incubated for 60 minutes at 24 C with various concentrations of [3H]-nociceptin. Nonspecific binding is determined in the presence of 1 mM unlabelled nociceptin. For competitive assay, the cell membrane preparations (4.17 ug/well) are incubated for 60 minutes at 24 C with 50 pM [3H]-nociceptin in the presence of various concentrations of JTC-801 (10 nM-10 uM). JTC-801 is dissolved in DMSO and diluted in binding buffer, and then added to the incubation mixture. Final concentration of vehicle is 1% DMSO in binding buffer. After incubation for 60 minutes, the membrane preparations are rapidly filtrated over Whatman GF/B glass filters which are pretreated with 0.1% polyethyleneimine, and the radioactivity on each filter is measured by liquid scintillation counting. IC50 value is calculated as the concentration of JTC-801 required to displace 50% inhibition of the [3H]-nociceptin.

JTC-801 is a selective opioid receptor-like1 (ORL1) receptor antagonist with IC50 of 94 nM, weakly inhibits receptors δ, κ, and μ.