Voltage activated K current in IB4-negative dorsal root ganglion neurons increased after GRO/KC incubation. The current densities of both the transient component and sustained components were increased after overnight incubation with GRO/KC (1.5 nM) in IB4-negative neurons. *, the effect of GRO/KC was significant at all points above 10 mV (left). There was no significant effect in IB4-positive neurons (right). Data are from 5 cultures; in IB4-negative neurons, N = 15 GRO/KC and 16 control cells; in IB4-Positive neurons, N = 16 GRO/KC and 15 control cells.