ADL-5859 (ADL5859 Hydrochloride) is a selective δ-opioid receptor agonist ( Ki: 0.8 nM), selectivity against opioid receptor κ, μ, and little inhibition for the hERG channel.

κ opioid receptor:37 nM(Ki), δ opioid receptor:0.8 nM(Ki), μ opioid receptor:32 nM(Ki)

ADL5859是一种具有1000倍选择性的δ-阿片受体激动剂，在δ-阿片受体上的Ki值分别为32 nM和37 nM。ADL5859对hERG通道的抑制活性较弱，其IC50为78 μM。ADL5859针对δ阿片受体的EC50为20 nM。[1]

在3 mg/kg口服剂量的筛选下, ADL5859能够完全逆转炎症爪部的高敏反应。ADL5859在FCA机械高敏反应测定中的口服ED50为1.4 mg/kg。通过预处理δ阿片受体拮抗剂纳曲酮（0.3 mg/kg皮下注射），ADL5859（3 mg/kg, 口服）产生的抗高敏效应被逆转，从而证明了δ受体介导的效应。在大鼠强迫游泳试验中，ADL5859（3 mg/kg口服）产生显著的抗抑郁样活动，表现为显著减少静止时间并显著增加游泳时间。ADL5859（3 mg/kg口服）在大鼠和狗中的生物利用度分别为33％和66％。ADL5859通过招募外周Nav1.8表达神经元所表达的δ-阿片受体，高效减轻炎症性及神经病理性疼痛。

Membrane preparations from Chinese hamster ovary (CHO) cells stably expressing human κ, μ, or δ opioid receptors are prepared. The assay buffer used is composed of 50 mMtris(hydroxymethyl) aminomethaneHCl, pH 7.8, 1.0 mM ethylene glycol bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA free acid), 5.0 mM MgCl2 10 mg/L leupeptin, 10 mg/L pepstatin A, 200 mg/L bacitracin, and 0.5 mg/L aprotinin. After dilution in assay buffer and homogenization in a Polytron homogenizer for 30 seconds, membrane proteins (10-80 μg) in 250 μL of assay buffer are added to mixtures containing ADL5859 and [3H]diprenorphine (0.5-1.0 nM, 25000-50000 dpm) in 250 μL of assay buffer in 96-well deep-well polystyrene titer plates and incubated at room temperature for 60 minutes. Reactions are terminated by vacuum filtration with a Brandel MPXR-96T harvester through GF/B filters that have been pretreated with a solution of 0.5% polyethylenimine and 0.1% bovine serum albumin for at least 1 hour. The filters arewashed four times with 1.0 mL each of ice-cold 50 mM Tris-HCl, pH 7.8, and 30 μL of Microscint-20 is added to each filter. Radioactivity on the filters is determined by scintillation spectrometry in a Packard TopCount. [3H]Diprenorphine with a specific activity of 50 Ci/mmolisused. The Kd values for [3H]diprenorphine binding are 0.33 nM for the κ and μ receptors and 0.26 nM for the δ receptor. Receptor expression levels, determined as Bmax values from Scatchard analyses, are 4400, 4700, and 2100 fmol/mg of protein for the κ, μ, and δ receptors, respectively. Preliminary experiments are performed to show that no specific binding is lost during the wash of the filters, that binding achieved equilibrium within the incubation time and remained at equilibrium for at least an additional 60 minutes, and that binding is linear with regard to protein concentration. Nonspecific binding, determined in the presence of 10 μM unlabeled naloxone, is less than 10% of total binding.Protein is quantified by the method of Bradford. The data from competition experiments are fit by nonlinear regression analysis with the program Prism using the four-parameter equation for one-site competition, and Ki values are subsequently calculated from EC50 values by the Cheng-Prusoff equation.(Only for Reference)