Peptidergic nerves in human dental pulp

Abstract

The peptidergic innervation of human dental pulp was studied with indirect immunofluorescence and immunoperoxidase techniques. Pulpal nerve fibres displaying immunoreactivity for cholecystokinin, calcitonin gene-related peptide, C-terminal flanking peptide of neuropeptide tyrosine, leucine-enkephalin, methionine-enkephalin, neuropeptide K, neuropeptide tyrosine, peptide with N-terminal histidine and C-terminal isoleucine, somatostatin-28, substance P and vasoactive intestinal polypeptide were observed. Immunoreactive axon varicosities were detectable within radicular and coronal nerve trunks and within the nerve plexus of Raschkow in the para-odontoblastic region. Many peptidergic nerve fibres were observed in association with blood vessels of various sizes. Substance P- and calcitonin-gene-related peptide-immunoreactive axons were visible in the odontoblastic layer. The occurrence of VIP- and PHI-immunoreactive fibres lends support to the hypothesis that human tooth may be supplied by parasympathetic nerves. The immunocytochemical results here shown provide a morphological basis to previous experimental studies concerning the possible roles of neuropeptides in nociception mechanisms, control of the blood flow and modulation of the inflammatory response in dental tissues.

Expression of substance P, calcitonin gene-related peptide, β-endorphin and methionine-enkephalin in human dental pulp tissue after orthodontic intrusion: A pilot study

“…The presence of these two substances in dental pulp tissue concurs with the findings of previous reports. 5,19,[23][24][25] Although the origin of sensory neuropeptides lies in the trigeminal central tissue, optimal axonal transportation allows for such local storage in nerve terminals. 26 For endogenous opioids, the local source is mainly located in different cellular populations, such as immunocytes.…”

Interstitial Fluid Pressure in Normal and Inflamed Pulp

“…6), a finding which implicates these neuropeptides in blood flow regulation. However, not only the nerves associated with blood vessels, but also most nerves in the subodontoblast/odontoblast area (Casasco et al, 1990) and nerve fibers penetrating the dentinal tubules show immunoreactivity for CGRP and substance P (Byers, 1992;Heyeraas et al, 1993). These immunoreactive nerve fibers in dentin may very well represent branches of nerves terminating around the pulpal blood vessels.…”

Neural Control of Pulpal Blood Flow

“…In oro-facial tissues, VIP-immunoreactivity (IR) can thus be used as a marker for parasympathetic post-ganglionic neurons. VlP-containing nerve fibers have been found in the dental pulp of several species, including man (Uddman et al, 1980;Akai and Wakisaka, 1990;Casasco et al, 1990;Luthman et al, 1992), and intra-arterial injection of synthetic VIP in the picomolar range causes vasodilation in the cat pulp . An interesting finding is that the adjacent gingiva is sensitive to even lower doses of VIP.…”

“…3), can be explained by the presence of neuropeptide Y (NPY) in sympathetic terminals in the pulp of several species, including man (Uddman et al, 1984;Edwall et al, 1985;Wakisaka, 1990;Casasco et al, 1990;Luthmanetal., 1992;Heyeraas et al, 1993). The distribution of axons with NPY-IR is very similar to the distribution of axons with dopamine-p-hydroxylase, an enzyme involved in catecholamine synthesis (see Wakisaka, 1990).…”