FIGURE 2.

Example data for receptor function and radioligand binding at wild-type and mutant receptors. (A) Channel function was measured using a voltage-sensitive fluorometric dye on a FlexStation. Values from a series of experiments were normalized, averaged and fitted with a four-parameter logistic equation. The calculated EC₅₀ values are shown in Table 2. (B) K_d values were estimated using the 5-HT₃ antagonist [³H]granisetron. The examples show binding for single experiments, fitted with a one site binding equation. K_d values for a series of experiments were averaged for each mutant, and are presented in Table 1.