Figure 8
dFBr concentration-dependent potentiation of WT and mutant α4β2 nAChRs. Peak current of Xenopus oocytes expressing WT or mutant (α4)3(β2)2 nAChRs responses to 10 s application of 10 μM ACh in the absence or presence of increasing concentrations of dFBr were normalized to the peak current elicited by 10 µM ACh alone. Shown are data (Average ± SE) from at least 4 different oocytes. Data were fit to a single site model using Equation 1. Values of dFBr potentiation EC 50 /I max /h were: for WT (α4)3(β2)2, 1.0 ± 0.3 μM/580 ± 42%/1.1 ± 0.2; for (α4C254S)3(β2)2, 1.5 ± 0.5 μM/430 ± 31%/0.8 ± 0.1; and for (α4L291V)3(β2)2, 2.9 ± 1.9 μM/600 ± 136%/0.8 ± 0.2. For (α4L256F)3(β2)2, (α4E308V)3(β2)2, and (α4G613L)3(β2)2, inhibition at 10 μM dFBr were ~25, 45, and 65%, respectively.
