Figure 4.

AChE overexpression is associated with enlarged motoneuron perikarya. (A) Embryonic enlargement. Thoracic spinal cord sections from E17 transgenic (T) and control (C) mice were stained with cresyl violet, and the perikaryal areas in μm² of ventral horn cells measured. Presented are percent fractions of the total number of cresyl violet positive cells in each size group (67 control and 32 transgenic cells were measured). This analysis revealed overall enlargement of neurons in transgenic embryonic spinal cord (P < 0.05). (Inset) Representative cresyl violet-positive control (C) and transgenic (T) neurons from embryonic (E17) and 3-month-old (adult) mice are presented. Note that the enlarged neurons characteristic of transgenic animals maintain the normal polygonal morphology. (Size bar, 10 μm.) Arrows indicate motoneurons. (B) Adult enlargement. Separate size distributions for ventral horn neurons up to 150 μm² (Left) and larger than 150 μm² (Right) from adult mice are presented. Smaller cells (202 control and 186 transgenic cells), presumably interneurons and γ-motoneurons, showed similar perikaryal area distributions in transgenic and control animals. In contrast, the larger ventral horn cells, presumably α-motoneurons (44 control and 27 transgenic cells), preserved the embryonic trend of enlarged perikarya observed in transgenic animals (P < 0.02).