Fig. 2

Chronic treatment with ddC altered the membrane excitability properties of dorsal root ganglion (DRG) neurons in mice. Whole-cell patch-clamp electrophysiology was performed on cultured small-diameter lumbar DRG neurons (n = 3 neurons/mouse). a Representative microphotograph of a patched neuron approximately 24 μm in diameter. b, d Representative traces of action potentials elicited by step (b) and ramp (d) current injections of rheobase. c Resting membrane potential was altered by chronic treatment with ddC (n = 10). e ddC treatment reduced first spike latency and increased the action potential (AP) frequency. Data presented as the mean ± SEM. Asterisks indicate a significant difference (*P < 0.05, **P < 0.01) in spike frequency between the ddC-treated mice and the control mice (saline). n = 10 per group. f Spike count measured from traces as in d. Note that the increase in the number of spikes (mean ± SEM) between the mice treated with ddC and the control (saline) mice is significant at **P < 0.01. n = 10. g AP thresholds for generation of APs, obtained by the phase plot analysis of AP (mean ± SEM), are significantly different (*P < 0.05) between ddC-treated mice and the saline control mice. n = 10. Bonferroni correction for multiple comparisons