Voltage dependence of CN-induced current, from cell illustrated in Figure 5. A, Data obtained before, during, and after CN application; note intersection of control and test plots near −90 mV (indicated by arrow).B, The action of CN was strongly attenuated by 8-SPT.C, Difference currents—obtained by subtracting control values of currents (before CN application) from currents recorded in presence of CN—are the currents activated by the action of CN. Note that relatively large CN difference current (open circles) was much reduced by 8-SPT (closed circles).