Biogenic amine study in the spinal cord of experimental cervical myelopathy

Concentrations of norepinephrine (NE), dopamine (DA), and serotonin (5HT) within cervical spinal cord specimens were determined using rabbits as the experimental animals. The animals were divided into three groups according to clinical results after cord compression operations which were performed with screws. The first group showed no neurlogical deficit, the second showed symptoms of acute spinal cord injury, and the third showed symptoms of experimental cervical myelopathy. Amines were assayed in three cord segments; at the compression site, rostral, and caudal to the site. DA and 5HT showed no remarkable changes at any site in either group. Mean average was 0.033 microgram/gm +/- 0.009 for DA and 0.54 microgram/gm +/- 0.08 for 5HT. NE showed significant elevation (0.237 microgram/gm +/- 0.013) at the compression site of the experimental group of acute spinal cord injury as compared with controls (0.151 microgram/gm +/- 0.03). The experimental cervical myelopathy group had no significant changes in NE levels at any site. The effects of hypoxia were then examined within each group, using a closed dessicator to achieve an hypoxic state. NE was assayed as before, but the results were same and significant elevation of NE was also observed at the compression site of the experimental animals of acute spinal cord injury with hypoxia.