Neuropeptide Y-like immunoreactivity in the lumbosacral pia mater in normal cats and after sciatic neuroma formation.

An indirect immunohistochemical technique was used to identify neuropeptide Y (NPY)-immunoreactive nerve fibers in the lumbosacral pia mater of normal cats and in kittens previously subjected to sciatic nerve resection. It was shown that NPY-positive fibers both associated with blood vessels and lacking vascular relation occur in the pia mater of normal cats. After nerve lesion some fibers which were not associated with blood vessels ramified extensively in the pia mater and formed thin beaded branches which ended blindly.