Background
Org 27569 is an allosteric ligand of the cannabinoid receptor CB1[1].
Org 27569 has been reported to promote the agonist CP55940 binding to purified bimane-labeled CB1 receptor and act directly on the CB1 receptor, yet at the same time inhibit receptor function. In addition, org 27569 has shown the potent inhibition of electrically evoked contractions of the mouse vas deferens by WIN55212 with the pEC50 and Emax of 8.24 ±0.12 and 45.4%, respectively. Apart from these, the pKB and Logα values for org 27569 at the putative allosteric site on the CB1 receptor are 5.67±0.23 and 1.14±0.17, respectively[1, 2].
参考文献:
[1] Price MR1, Baillie GL, Thomas A, Stevenson LA, Easson M, Goodwin R, McLean A, McIntosh L, Goodwin G, Walker G, Westwood P, Marrs J, Thomson F, Cowley P, Christopoulos A, Pertwee RG, Ross RA. Allosteric modulation of the cannabinoid CB1 receptor. Mol Pharmacol. 2005 Nov;68(5):1484-95. Epub 2005 Aug 19.
[2] Fay JF1, Farrens DL. A key agonist-induced conformational change in the cannabinoid receptor CB1 is blocked by the allosteric ligand Org 27569. J Biol Chem. 2012 Sep 28;287(40):33873-82. Epub 2012 Jul 30.
Protocol
Kinase experiment: | Binding assays are performed with the CB1 receptor agonist [3H]CP 55,940 (0.7 nM) and the CB1 receptor antagonist [3H]SR 141716A (1.2 nM), 1 mg/mL BSA and 50 mM Tris buffer containing 0.1 mM EDTA and 0.5 mM MgCl2, pH 7.4, in a total assay volume of 500 μL. Binding is initiated by the addition of mouse brain membranes (30 μg). Assays are carried out at 37°C for 60 min before termination by addition of ice-cold wash buffer (50 mM Tris buffer and 1 mg/mL BSA) and vacuum filtration using a 24-well sampling manifold and Whatman GF/B glass-fiber filters that have been soaked in wash buffer at 4°C for 24 h. Each reaction tube is washed five times with a 4-mL aliquot of buffer. The filters are oven-dried for 60 min and then placed in 5 mL of scintillation fluid, and radioactivity is quantitated by liquid scintillation spectrometry. Specific binding is defined as the difference between the binding that occurs in the presence and absence of 1 μM concentrations of the corresponding unlabeled ligand and is 70 to 80% of the total binding. |
Animal experiment: | Following a 1-week acclimation period, CB1 (+/+) and (?/?) mice are food-deprived, given an intraperitoneal injection of Org27569 (30 mg/kg), rimonabant (10 mg/kg; positive control), or vehicle at 23 h, and placed in a plastic cage with access to water. A premeasured amount (2.3-2.6 g) of sweet cereal or standard chow is placed in the test cage from 24 to 26h. All mice receive each treatment condition in a counterbalanced design, with at least 96 h between test days. |
参考文献: [1]. Jing L, et al. Effects of the cannabinoid CB? receptor allosteric modulator ORG 27569 on reinstatement of cocaine- and methamphetamine-seeking behavior in rats. Drug Alcohol Depend. 2014 Oct 1;143:251-6.
[2]. Fay JF, et al. A key agonist-induced conformational change in the cannabinoid receptor CB1 is blocked by the allosteric ligand Org 27569. J Biol Chem. 2012 Jul 30.
[3]. Gamage TF, et al. In-vivo pharmacological evaluation of the CB1-receptor allosteric modulator Org-27569. Behav Pharmacol. 2014 Apr;25(2):182-5.
[4]. Price MR, et al. Allosteric modulation of the cannabinoid CB1 receptor. Mol Pharmacol. 2005 Nov;68(5):1484-95.
[5]. Baillie GL, et al. CB(1) receptor allosteric modulators display both agonist and signaling pathway specificity. Mol Pharmacol. 2013 Feb;83(2):322-38. |
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