Fig. 3.
Dose–response curves for agonists and partial agonists in the presence and absence of 1 μM dFBr. A, ACh. B, nicotine. C, choline. D, cytisine. dFBr and the appropriate concentration of agonist or partial agonist were coapplied to Xenopus oocytes expressing α4β2 receptors (mRNA injected at a ratio of 1α/1β). The peak current was measured, and responses were normalized to currents elicited by 1 mM ACh applied alone to the same oocyte. Each data point represents the combined data from at least four different experiments from a minimum of two different oocytes harvested from different frogs. Error bars indicate ± S.E.M. pEC50, Imax, and Hill slope (nH) were calculated by using nonlinear curve fitting algorithms and are shown in Table 1.