Immunohistochemical observation on neuropeptides around the blood vessel in feline dental pulp.

Recent advances in immunohistochemistry have revealed the distribution of various neuropeptides in several mammalian dental pulps. These neuropeptides are substance P, neurokinin A, calcitonin gene-related peptide, vasoactive intestinal polypeptide, and neuropeptide Y. Nerve fibers showing immunoreactivity for these neuropeptides are mainly localized around the pulpal vessels, but some are apart from the blood vessel. The distribution of substance P-, neurokinin A-, and calcitonin gene-related peptide-containing nerve fibers is very similar; it appears that these three neuropeptides may be contained in the same nerve fibers. Denervation experiments indicate that substance P-, neurokinin A- and calcitonin gene-related peptide-containing nerve fibers originate from the trigeminal ganglion and that neuropeptide Y-containing nerve fibers come from the superior cervical ganglion. However, the exact origin of vasoactive intestinal polypeptide-containing fibers still remains unknown. These immunohistochemical data indicate that neuropeptides localized around the blood vessel may play a significant role in the regulation of the blood flow in the dental pulp.