Figure 3.

Inhibition of [³H]-granisetron binding to mutant and wildtype receptors by lerisetron. Competition binding assays were performed as described in Materials and Methods. Each point represents a mean ± SE of n>4 experiments. K_i values calculated from this data and the relative magnitude of the shift in Ki compared to wildtype receptors are shown in Table 2. Y140A produced no significant change in K_i values. W89F, W89Y and R91A mutations produced moderate increases in K_i. Y142A and Y152A mutations resulted in increases in K_i of 160 and 190 fold respectively.