COERULOSPINAL FIBER REGENERATION IN TRANSECTED FELINE SPINAL-CORD

After complete cat spinal cord transection, a collagen matrix was used to bridge the gap. Vascular supply was increased to the transection s ite with an omental pedicle. Before hardening, either 4-aminopyridine, laminin, glia maturation factor, or lipid angiogenic factor were mixe d into the collagen. Surgically reconstructed animals were compared to transection-only controls and observed for 90 days. Fluoro-Gord was i njected distal to the transection site on day 75. Immunocytochemical e xamination of brain and spinal cord tissue was done on day 90. Examina tion revealed supraspinal catecholaminergic fibers present in the coll agen bridge and distal cord tissue only in cats with surgical reconstr uction. Fluoro-Gold particles were found localized in locus coeruleus and other noradrenergic pontine neurons. Distal to the transection, do uble immunostaining with synaptophysin and tyrosine hydroxylase or dop amine-beta-hydroxylase revealed dot-like deposits closely apposed to p reganglionic sympathetic neurons suggestive of synaptic connectivity t o these targets. Results indicate that considerable outgrowth of speci fic supraspinal fibers can be induced following spinal transection and reconstruction, and that such fibers may be extending and contacting appropriate distal target tissue in the cord.