CHEMBL5733999

Inhibition Assay: Human NK-2 The affinity of compounds of the invention for the NK-2 receptor was evaluated in CHO recombinant cells which express the human NK-2 receptor. Membrane suspensions were prepared from these cells. The following radioligand [125I]-Neurokinin A (PerkinElmer Cat#NEX252) was used in this assay. Binding assays were performed in a 25 mM HEPES/1 mM CaCl2/5 mM MgCl2/0.5% BSA/10 μg/ml saponin, at pH 7.4. Binding assays consisted of 25 μl of membrane suspension (approximately 3.75 μg of protein/well in a 96 well plate), 50 μl of compound or reference ligand (Neurokinin A) at increasing concentrations (diluted in assay buffer) and 0.1 nM [125]-Neurokinin A. The plate was incubated 60 min at 25° C. in a water bath and then filtered over GF/C filters (Perkin Elmer, 6005174, presoaked in assay buffer without saponine for 2 h at room temperature) with a Filtration unit (Perkin Elmer). The radioactivity retained on the filters was measured by using the TopCount-NXT reader (Packard). Competition curves were obtained for compounds of the invention and the concentrations of compounds which displaced 50% of bound radioligand (IC50) were determined and then apparent inhibition constant Ki values were calculated by the following equation: Ki=IC50/(1+[L]/KD) where [L] is the concentration of free radioligand and KD is its dissociation constant at the receptor, derived from saturation binding experiments.