Left: the ab118649 ligand (100 nm) binding to live CHO cells expressing histamine H3 receptors. Right: Binding blocked by the unlabelled competitor rantidine (10 mM). Nuclei have been counter-stained with Hoechst.
To determine the apparent KD for ab118649, cells were treated with varying concentrations of histamine alone, or in the presence of 1 µM ab118649, and the cyclic-AMP induced expression of SPAP measured. The apparent KD was calculated from the rightward shift of the agonist response curve in the presence of ab118649, compared to the response curve for the agonist alone. Antagonist –log KD values for H1= 6.55, H2 =5.71, H3 = 7.09
To determine the apparent KD for ab118649, cells were treated with varying concentrations of histamine alone, or in the presence of 1 µM ab118649, and the cyclic-AMP induced expression of SPAP measured. The apparent KD was calculated from the rightward shift of the agonist response curve in the presence of ab118649, compared to the response curve for the agonist alone. Antagonist –log KD values for H1= 6.55, H2 =5.71, H3 = 7.09