Fig. 1.
A, Graph showing variations in surface area (μm2) of growth cones from minor processes (MP), prospective axons (pAxon), and axons (Axon) of stage 2 or 3 hippocampal pyramidal neurons.B, Frequency histogram analysis showing variations in growth cone surface among MP, prospective axons, and axons of stage 2–3 hippocampal pyramidal neurons. C, A confocal micrograph showing a stage 2 neuron with several minor neurites; note that one of them displays a large growth cone. The cell was double labeled with an mAb against tyrosinated α-tubulin (green) and rhodamine phalloidin (red). D, E, High-power confocal images showing the distribution of microtubules (green) and F-actin (red) in large growth cones from stage 2 hippocampal pyramidal neurons. Note that the growth cones display a large, flattened lamellipodial veil with short actin ribs and that microtubules enter the central growth cone region.F, G, High-power fluorescence micrographs showing the distribution of tyrosinated α-tubulin (F) and F-actin (G) in a small growth cone of a stage 2 hippocampal pyramidal neuron. H, Red-greenoverlay of the images shown in F and G. Note that F-actin (red) occupies the central and peripheral region of the growth cone and that microtubules (green) end at its base. Scale bars: C, 10 μm; D, E, 5 μm; F–H, 7 μm.