Immunoreactivity for glutamic acid decarboxylase and several neuropeptides in the spinal cord of the raccoon.

The peroxidase-antiperoxidase method was used to examine major immunohistochemical features of the spinal cord of adult raccoons. The lateral portions of the ventral horn contained many large multipolar neurons that showed cholecystokinin-like immunoreactivity, suggesting the coexistence of cholecystokinin with acetylcholine in a subset of motoneurons. The dorsal horn revealed unique but overlapping patterns of immunoreactivity for glutamic acid decarboxylase, somatostatin, substance P, vasoactive intestinal polypeptide and cholecystokinin. The data imply that some of the peptides may coexist within the same dorsal root ganglion cells and their spinal cord processes.