Concentration-dependent stimulation of I
by NGEN in NSC-34 cells. In these experiments, each cell was hyperpolarized from -20 to -50 mV with a duration of 2 sec. (A) Original current traces obtained in the control and during exposure to NGEN. a: control; b: 3 μM NGEN; c: 10 μM NGEN; d: 30 μM NGEN. The upper part indicates the voltage protocol used. (B) Concentration-response relationship for NGEN-induced increase of I K(M) (i.e., linopirdine-sensitive current) measured at the end of hyperpolarizing pulses (mean ± SEM; n = 9-12 for each point). Smooth blue line represents the best fit to the Hill equation as described in Methods.