Fig. 2.

Effect of RA precursors and a RARβ agonist in neurite outgrowth in neuron and neuron-NG2 cultures. (a and b) CD2019 induces neurite outgrowth in cortical neuron cultures but not retinal nor retinol. Upper panel shows lower magnification images (a), scale bar is 300 μm and lower panel (b) higher magnification pictures of the same cultures, scale bar is 50 μm. (c–d) CD2019, retinal and retinol increase neurite length in neuron-NG2 + cells cultures. The upper panel shows lower magnification images, scale bar is 100 μm (c) and the lower panel (d) shows images of the same cultures in higher magnification, scale bar is 50 μm. The white arrows indicate the points of physical contact between the NG2 + cells and neurites. (e) Quantification of the length of the longest neurites per culture condition obtained from six random fields and done in triplicate per culture condition. (f) NG2 + cells attract and guide growing neurite in the presence of retinal and retinol: there is a significant increase in the % of growing neurites that contact with the NG2 + cells, illustrated by the white arrows in these photomicrographs. Scale bar is 30 μm. Data represent Mean ± SEM. **p ≤ 0.01***p ≤ 0.001, one-way ANOVA followed by Tukey's test.