Effects of expressing human AChE on the growth ofXenopus spinal neurons. Composite concentric line drawings were made from video images of 12 isolated spinal neurons at 6, 7, 8, and 9 hr after cell plating. The center of the neuronal soma (deleted from this image) was placed in the center of each drawing. Note consistent overall neurite length promotion in neurons that expressed AChE-E6 but not AChE-I4. Neurons derived from uninjected blastomeres served as controls. Scale bar, 20 μm.