Figure 9
Effect of dFBr on the ACh dose-response curve of mutant α4β2 nAChRs. Currents elicited by Xenopus oocytes expressing mutant (α4)3(β2)2 nAChRs in response to 10-second applications of increasing concentrations of ACh (alone (○) or +1 µM dFBr (▲)) were recorded and normalized to peak currents elicited by 1 mM ACh alone. Replicas from the same oocyte were averaged and the Average ± SE of at least 3 oocytes were plotted and fit to a single site model using Equation 1. ACh I max in the presence of 1 µM dFBr calculated from curve fitting for (α4C254S)3 (β2)2, (α4L256F)3 (β2)2, (α4L260M)3 (β2)2, (α4E308V)3 (β2)2, (α4F316L)3 (β2)2, (α4F606Y)3 (β2)2, (α4G613L)3(β2)2 were 190 ± 08, 142 ± 08, 250 ± 36, 110 ± 06, 148 ± 12, 159 ± 07, and 157 ± 19%, and the probability (P) that Imax in the presence of 1 µM dFBr were different from normalized current response to 1 mM ACh alone (Imax = 100) were <0.001, 0.057, <0.001, 0.602, 0.031, 0.001, 0.012, respectively.
