| Assay Method Information | |
| | κ-Opioid Receptor Binding Assay |
| Description: | κ-Opioid Receptor Binding Assay Procedures: Membranes from HEK-293 cells, CHO cells or U-2 OS cells expressing the recombinant human kappa opioid receptor (κ) were prepared by lysing cells in ice cold hypotonic buffer (2.5 mM MgCl2, 50 mM HEPES, pH 7.4) (10 mL/10 cm dish) followed by homogenization with a tissue grinder/Teflon pestle. Membranes from a cell line naturally expressing kappa opioid receptor can also be used. Membranes were collected by centrifugation at 30,000×g for 15 min at 4° C. and pellets were resuspended in hypotonic buffer to a final concentration of 1-3 mg/mL. Protein concentrations were determined using the BioRad protein assay reagent with bovine serum albumen as standard. Aliquots of κ receptor membranes were stored at −80° C.Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well. |
| Affinity data for this assay | |
|---|---|
| If you find an error in this entry please send us an E-mail | |