Figure 2.
Voltage-independent inhibition of IAcCho by Zn2+ in WTα7 oocytes. (A) The percentage block is the inhibition of IAcCho (AcCho, 150 μM) by Zn2 (20 μM) at various holding potentials. Each point is the mean ± SEM of 7 oocytes and 2 donors. Oocytes were pretreated with Zn2+ as in Fig. 1. (B) Current– voltage relation in one oocyte expressing WTα7 nAcChoRs. Peak currents evoked at various holding potentials by 150 μM AcCho (■) and by 150 μM AcCho coapplied with 30 μM Zn2+ (□). AcCho was applied at 3-min intervals and Zn2+ for 30 s before coapplication with AcCho. Solid lines represent second-order polynomial fits to the data. Note strong current rectification at positive potentials.