Innervation of the Human Incisive Papilla: Comparison with Other Oral Regions

Abstract

Immunohistochemistry for several neurochemical substances was performed on the human incisive papilla and other oral structures. Sodium channel alpha subunit 7 (SCN7A) protein-immunoreactive (IR) Schwann cells and protein gene product 9.5 (PGP 9.5)-IR nerve fibers made nerve plexuses beneath the epithelium of the palate, including the incisive papilla, tongue, and lip. SCN7A immunoreactivity could also be detected in lamellated and nonlamellated capsules of corpuscle endings. Lamellated SCN7A-IR corpuscle endings were mostly restricted to the mucous and cutaneous lips. These endings had thick and spiral-shaped PGP 9.5-IR axons without ramification. Nonlamellated SCN7A-IR corpuscle endings were most numerous in the incisive papilla among the oral regions. On the basis of axonal morphology, the nonlamellated endings were divided into simple and complex types. PGP 9.5-IR terminal axons in the simple type ran straight or meandered with slight ramification, whereas those in the complex type were densely entangled with abundant ramification. Substance P (SP)-, calcitonin gene-related peptide (CGRP)-, and transient receptor potential cation channel subfamily V member 2 (TRPV2)-IR varicose fibers were rarely seen beneath the epithelium of oral structures. The present study indicates that the human incisive papilla has many low-threshold mechanoreceptors with nonlamellated capsules. SP-, CGRP-, and TRPV2-containing nociceptors may be infrequent in the incisive papilla and other oral regions.

Distribution and possible function of galanin about headache and immune system in the rat dura mater

“…Data about the cerebral falx, other cerebral portions, and cerebellar dura mater were obtained from 1, 3, and 14 digital images (each image size = 660 µm × 820 µm), respectively, in each section. The proportion of their length to the area of each region was calculated for immunoreactive density 51 – 53 . The average of such immunoreactive density was recorded for each animal.…”

Distribution of neuronal cells which contain dopamine β‐hydroxylase, tyrosine hydroxylase, neuropeptide Y and vasoactive intestinal polypeptide in the human internal carotid nerve

“…This peptide is also present in the human SCG, and probably plays a role in the sympathetic nervous system (Kokubun et al, 2019). On the other hand, substance P (SP) and calcitonin gene‐related peptide (CGRP) are expressed by nociceptive neurons in the sensory ganglion (Endo, Sato, Yajima, Igarashi, & Ichikawa, 2018; Ju et al, 1987; Sato et al, 2017; Sugimoto, Fujiyoshi, Xiao, He, & Ichikawa, 1997; Yajima et al, 2015; Yajima, Sato, Shimazaki, & Ichikawa, 2019). A previous study has demonstrated the presence and distribution of neuropeptides in the human internal carotid ganglion.…”