Effect of GI‐530159 on small DRG neuron firing properties. (A) Normal firing of individual DRG neuron in response to current injection (black trace) is inhibited by GI‐530159 (1 μM, red trace). (B, C) GI‐530159 inhibits action potential firing in some small DRG neurons. (D–F) GI‐530159 (1 μM) hyperpolarizes the membrane potential of small DRG neurons. In (D), membrane potential in each individual neuron is hyperpolarized from −53.6 ± 1.5 to −57.1 ± 1.5 mV (n = 14 individual neurons, P < 0.05, paired t‐test) by GI‐530159 (1 μM). In (E), the average membrane potential in neurons from a given rat is significantly hyperpolarized from −54.0 ± 2.0 to −57.8 ± 1.4 mV (n = 7 rats, P < 0.05, paired t‐test, Figure 7D) by GI‐530159 (1 μM). In (C, F), six neurons with clear inhibition of firing are shown in red, and six neurons where there was no inhibition of firing are in blue. Two neurons, which were not clearly defined, are shown in grey. Each recorded neuron was from an independent coverslip, and the 14 neurons were taken from seven independent preparations of DRG neurons.