| Assay Method Information | |
| | Binding Assay |
| Description: | Cell membrane proteins (Perkin Elmer) wherein human muscarinic M3 receptor was overexpressed, [3H]-methyl scopolamine and test compounds in various concentration were cultured in 0.2 ml of Tris-HCl buffer at 25° C. for 120 minutes. The same was filtered under suction through glass fiber filter (Whatman GF/B), and then the filter was washed 5 times with 1 ml of Tris-HCl buffer. The radioactivity of [3H]-methyl scopolamine adsorbed on the filter was measured by a liquid scintillation counter. Non-specific binding was evaluated under existence of 5 μM of atropine. Affinity of the compound of the present invention to muscarinic M3 receptor was calculated as the dissociation constant (Ki), which can be calculated from concentration (IC50) of test compounds inhibiting 50% of binding of [3H]-methyl scopolamine (i.e. labeled ligand) according to Cheng and Prusoff [Cheng and Prusoff, Biochem. Pharmacol., 22, 3099, 1973]. In following Table, compounds having stronger binding affinity to human muscarinic M3 receptor have lower dissociation constant (Ki). |
| Affinity data for this assay | |
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