Laminin (LM) β2 inhibition is calcium dependent. Stage 16 dissociated neural tubes were cultured and neurons identified by staining for β-tubulin. A, B, Neurite outgrowth on LM is inhibited by addition of the laminin β2 fragment (LRE). Scale bar, 50 μm. C, D, Incubating neurons cultured on LM plus the β2 LRE fragment in 5 μm ω-conotoxin or in calcium-free medium prevents inhibition of neurite outgrowth indicating calcium dependence of LRE inhibition. E, Incubating neurons grown on LM alone in calcium-free medium does not lead to increases in neurite extension. F, Neurite extension on LRE is rescued by preventing calcium influx through CaV2.2 (n ≥ 250 neurons from ≥7 embryos; *p < 0.05). Error bars indicate SEM.