The L-type VGCC EGL-19 and internal stores contribute to the axotomy calcium transient and are required for regrowth. A, Time frames from videos collected during axotomy performed on control and egl-19(ad695gf) worms expressing Pmec-4-G-CaMP 2.0 (juEx2116). B, Effects of egl-19(ad695gf) (blue trace) and the EGL-19 inhibitor Nemadipine-A (red trace) on decay of the G-CaMP transient, measured close to the site of axotomy; representative traces are shown. C, egl-19(gf) mutants display increased axon regrowth 6 and 24 h after axotomy. D, At 3.5 h, most wild-type animals do not show sprouting of the injured stump (arrowhead), whereas ∼50% of egl-19(gf) animals display visible sprouting (arrowhead). Red arrows in D, F, and H indicate position of axotomy. E, Nemadipine-A (Nem-A) reduces regrowth of PLM axons at 10 and 24 h. F, PLM regrowth at 24 h in drug control conditions and after Nemadipine-A treatment. G, Touch neuron-specific expression of super sponge transgenes (juEx2410) has a stronger inhibitory effect than do control sponge transgenes (juEx2412);zdIs5 background. H, Representative PLM regrowth in control sponge- and super sponge-expressing animals. Numbers in bars indicate the number of axons from at least two independent experimental groups. Scale bars, 10 μm. Statistics: t test; *p < 0.05; **p < 0.01; ***p < 0.001. WT, Wild type; ns, not significant.