FIGURE 5.

[¹²⁵I]RTI-55 dissociation rates and allosteric potencies of escitalopram and talopram are unaffected by the L406E mutation. A, representative time course for dissociation of [¹²⁵I]RTI-55 from HEK293-MSR membranes expressing SERT WT (left) or L406E (right) in the presence of increasing concentrations of escitalopram. The dissociation shows exponential decay and escitalopram decrease the dissociation rate of [¹²⁵I]RTI-55 in a dose-dependent manner. The experiment was also conducted using increasing concentrations of talopram as allosteric modulator. B, dissociation rates are plotted as a function of the concentration of escitalopram (left) or talopram (right). From the sigmoidal dose-response curve, the allosteric potency (EC₅₀) for escitalopram and talopram can be derived. The allosteric potency of escitalopram and talopram was found to be identical in SERT WT and L406E. Independent dissociation experiments were repeated three times.