Fig. 4.

Cd²⁺ and Ni²⁺ are less effective than Zn²⁺at potentiating neuronal nAChRs. The effects of Cd²⁺(▿) and Ni²⁺ (⋄) on ACh (1 μm)-induced current responses of α4β4-expressing oocytes are plotted as a percentage of the current obtained with 1 μm ACh alone (mean ± SEM of 3–5 oocytes). Potentiating and inhibiting phases were fit separately as described in Materials and Methods. Data from Figure 2C showing the effect of Zn²⁺ (○) are included for comparison. Some error bars are obscured by symbols.