Figure 4.

Association binding of [³H]mepyramine and [³H]levocetirizine in the presence of competing unlabeled ligands at the H₁R at 25 °C. The kinetic binding of [³H]mepyramine to H₁R-expressing cell homogenates was measured with various concentrations of either mepyramine (a) doxepin (b) or levocetirizine (c). Similarly, the kinetic binding of [³H]levocetirizine to H₁R-expressing cell homogenates was measured in competition with various concentrations of either mepyramine (d) doxepin (e) or levocetirizine (f). Representative graphs are shown of ≥3 experiments and each condition was measured in duplicate. Extracted binding constants and statistical information are shown in Table 2 and Supplementary Table 2.