The L-type calcium channel agonist FPL 64176 inhibits DRG axon outgrowth. A, FPL 64176 inhibits DRG axon outgrowth on laminin in a concentration-dependent manner. B, FPL 64176 has no effect on axon length of DRG neurons cultured on CSPG. C, βIII-tubulin immunostaining of DRG neurons cultured on laminin for 24 hours in the presence of FPL 64176 (33.33 μM) or vehicle. Data are mean ± S.E. n = 12-36. Scale bar, 100 μm. *, p < 0.05; ****, p < 0.0001, one-way ANOVA, post hoc Dunnett.