Dogs were made paraplegic by complete mid-thoracic spinal cord transection. At one, three, eight, and twelve weeks post-transection the lumbar cord was removed and the dorsal grey matter microdissected from L2–3 and the content of ɤ-aminobutyric acid (GABA) determined. An initial decrease in GABA levels was followed by a gradual increase in content which correlated with the progressive development of spinal spasticity. By twelve weeks post-transection, GABA was elevated 68% above controls.

Dogs were made paraplegic by complete mid-thoracic spinal cord transection. The content of glycine, glutamate, aspartate, and γ-aminobutyric acid were determined in ventral and central grey matter from the lumbar enlargement of the spinal cord at 1, 3 and 8 weeks after transection. A rapid decrease in the content of aspartate and glycine accompanied the onset of spasticity. By the eight week post-transection, aspartate and glycine had decreased to less than 50% of control levels.