Bright-field photomicrographs showing neutral red-stained DL motoneurons overlaid with autoradiography grains of NMDA subunit NR2A mRNA (left) and AMPA subunit GluR2 mRNA (right). Top, An uninjured animal shows moderate levels of mRNA expression.Middle, A 12.5 mm SCI animal has similar levels of mRNA expression. Bottom, A 50 mm SCI animal shows high expression of both NR2A and GluR2 subunit mRNAs. Scale bar, 20 μm.