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

2018 ◽  
Vol 205 (2) ◽  
pp. 93-104
Author(s):  
Chiaki Endo ◽  
Tadasu Sato ◽  
Takehiro Yajima ◽  
Kaoru Igarashi ◽  
Hiroyuki Ichikawa

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.

2020 ◽  
Vol 21 (17) ◽  
pp. 6221 ◽  
Author(s):  
Ramón Cobo ◽  
Jorge García-Piqueras ◽  
Yolanda García-Mesa ◽  
Jorge Feito ◽  
Olivia García-Suárez ◽  
...  

The vertebrate skin contains sensory corpuscles that are receptors for different qualities of mechanosensitivity like light brush, touch, pressure, stretch or vibration. These specialized sensory organs are linked anatomically and functionally to mechanosensory neurons, which function as low-threshold mechanoreceptors connected to peripheral skin through Aβ nerve fibers. Furthermore, low-threshold mechanoreceptors associated with Aδ and C nerve fibers have been identified in hairy skin. The process of mechanotransduction requires the conversion of a mechanical stimulus into electrical signals (action potentials) through the activation of mechanosensible ion channels present both in the axon and the periaxonal cells of sensory corpuscles (i.e., Schwann-, endoneurial- and perineurial-related cells). Most of those putative ion channels belong to the degenerin/epithelial sodium channel (especially the family of acid-sensing ion channels), the transient receptor potential channel superfamilies, and the Piezo family. This review updates the current data about the occurrence and distribution of putative mechanosensitive ion channels in cutaneous mechanoreceptors including primary sensory neurons and sensory corpuscles.


2016 ◽  
Vol 203 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Tadasu Sato ◽  
Nobuyuki Sasahara ◽  
Noriyuki Kanda ◽  
Yu Sasaki ◽  
Yu Yamaguma ◽  
...  

Immunohistochemistry for protein gene product 9.5 (PGP 9.5), calcitonin gene-related peptide (CGRP) and the transient receptor potential cation channel subfamily V member 2 (TRPV2) was performed on human paranasal sinuses. It was found that in the paranasal sinuses, mucous membranes contain PGP 9.5-immunoreactive (PGP 9.5-IR) nerve fibers. Such nerve fibers terminated around large blood vessels as fine varicosities. Isolated PGP 9.5-IR nerve fibers were scattered beneath the epithelium. Glandular tissues were also innervated by PGP 9.5-IR nerve fibers. These fibers were numerous in the maxillary and ethmoid sinuses, and relatively rare in the frontal and sphenoid sinuses. CGRP-IR nerve fibers were common in the maxillary sinus whereas TRPV2-IR nerve fibers were abundant in the ethmoid sinus. They were located around large blood vessels in the lamina propria. Many subepithelial nerve fibers contained TRPV2 immunoreactivity in the ethmoid sinus. CGRP- and TRPV2-IR nerve fibers were very infrequent in the frontal and sphenoid sinuses. In the human trigeminal ganglion (TG), sensory neurons contained CGRP or TRPV2 immunoreactivity. CGRP-IR TG neurons were more common than TRPV2-IR TG neurons. CGRP-IR TG neurons were of various cell body sizes, whereas TRPV2-IR TG neurons were mostly medium-to-large. In addition, human spinal and principal trigeminal sensory nuclei contained abundant CGRP- and TRPV2-IR varicosities. This study indicates that CGRP- and TRPV2-containing TG neurons probably innervate the paranasal sinus mucosae, and project into spinal and principal trigeminal sensory nuclei.


2021 ◽  
Vol 22 (7) ◽  
pp. 3360
Author(s):  
Mee-Ra Rhyu ◽  
Yiseul Kim ◽  
Vijay Lyall

In addition to the sense of taste and olfaction, chemesthesis, the sensation of irritation, pungency, cooling, warmth, or burning elicited by spices and herbs, plays a central role in food consumption. Many plant-derived molecules demonstrate their chemesthetic properties via the opening of transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) channels. TRPA1 and TRPV1 are structurally related thermosensitive cation channels and are often co-expressed in sensory nerve endings. TRPA1 and TRPV1 can also indirectly influence some, but not all, primary taste qualities via the release of substance P and calcitonin gene-related peptide (CGRP) from trigeminal neurons and their subsequent effects on CGRP receptor expressed in Type III taste receptor cells. Here, we will review the effect of some chemesthetic agonists of TRPA1 and TRPV1 and their influence on bitter, sour, and salt taste qualities.


2017 ◽  
Vol 204 (5-6) ◽  
pp. 293-303 ◽  
Author(s):  
Masatoshi Fujita ◽  
Tadasu Sato ◽  
Takehiro Yajima ◽  
Eiji Masaki ◽  
Hiroyuki Ichikawa

TRPC (transient receptor potential cation channel subfamily C) members are nonselective monovalent cation channels and control Ca2+ inflow. In this study, immunohistochemistry for TRPC1, TRPC3, and TRPC4 was performed on rat oral and craniofacial structures to elucidate their distribution and function in the peripheries. In the trigeminal ganglion (TG), 56.1, 84.1, and 68.3% of sensory neurons were immunoreactive (IR) for TRPC1, TRPC3, and TRPC4, respectively. A double immunofluorescence method revealed that small to medium-sized TG neurons co-expressed TRPCs and calcitonin gene-related peptide. In the superior cervical ganglion, all sympathetic neurons showed TRPC1 and TRPC3 immunoreactivity. Parasympathetic neurons in the submandibular ganglion, tongue, and parotid gland were TRPC1, TRPC3, and TRPC4 IR. Gustatory and olfactory cells were also IR for TRPC1, TRPC3, and/or TRPC4. In the musculature, motor endplates expressed TRPC1 and TRPC4 immunoreactivity. It is likely that TRPCs are associated with sensory, autonomic, and motor functions in oral and craniofacial structures.


2019 ◽  
Vol 95 (2) ◽  
pp. 251-257
Author(s):  
Aoi Tanaka ◽  
Yoshiyuki Shibukawa ◽  
Masahito Yamamoto ◽  
Shinichi Abe ◽  
Hitoshi Yamamoto ◽  
...  

AbstractOdontoblasts act as dentin formation and sensory receptors. Recently, it was reported that transient receptor potential ankyrin (TRPA) 1, TRP vanilloid (TRPV) 4 and pannexin 1 (PANX-1) play important roles in odontoblast sensory reception. However, it is not known when odontoblasts begin to possess a sense reception function. The aim of this study was to clarify the development of odontoblasts as sense receptors. Sections of mandibular first molars from postnatal day (PN) 0 to PN12 Wistar rats were prepared for hematoxylin–eosin staining. Immunohistochemically, we used anti-dentin sialoprotein (DSP), anti-TRPA1, anti-TRPV4, anti-PANX-1, and anti-neurofilament (NF) antibodies. In addition, we investigated TRPA1 and TRPV4 expression by reverse transcriptional quantitative polymerase chain reaction (RT-qPCR). At PN0, undifferentiated odontoblasts showed no immunoreaction to anti-DSP, anti-TRPA1, anti-TRPV4, or anti-PANX-1 antibodies. However, immunopositive reactions of these antibodies increased during odontoblast differentiation at PN3 and PN6. An immunopositive reaction of the anti-NF antibody appeared in the odontoblast neighborhood at PN12, when the odontoblasts began to form root dentin, and this appeared later than that of the other antibodies. By RT-qPCR, expression of TRPA1 at PN6 was significantly lower than that at PN0 (p < 0.05) and PN3 (p < 0.01). Expression of TRPV4 at PN6 was significantly lower than that at PN0 (p < 0.01) and PN3 (p < 0.01). The results of this study suggest that odontoblasts may acquire sensory receptor function after beginning to form root dentin, when TRPA1, TRPV4, PANX-1 channels, and nerve fibers are completely formed.


Cephalalgia ◽  
2020 ◽  
Vol 40 (12) ◽  
pp. 1310-1320
Author(s):  
Anna Koldbro Hansted ◽  
Lars Jørn Jensen ◽  
Jes Olesen ◽  
Inger Jansen-Olesen

Background The Transient Receptor Potential Ankyrin 1 (TRPA1) channel might play a role in migraine. However, different mechanisms for this have been suggested. The purpose of our study was to investigate the localization and significance of TRPA1 channels in rat pial and dural arteries. Methods Immunofluorescence microscopy was used to localize TRPA1 channels in dural arteries, pial arteries, dura mater and trigeminal ganglion. The genuine closed cranial window model was used to examine the effect of Na2S, a donor of the TRPA1 channel opener H2S, on the diameter of pial and dural arteries. Further, we performed blocking experiments with TRPA1 antagonist HC-030031, calcitonin gene-related peptide (CGRP) receptor antagonist olcegepant and KCa3.1 channel blocker TRAM-34. Results TRPA1 channels were localized to the endothelium of both dural and pial arteries and in nerve fibers in dura mater. Further, we found TRPA1 expression in the membrane of trigeminal ganglia neuronal cells, some of them also staining for CGRP. Na2S caused dilation of both dural and pial arteries. In dural arteries, this was inhibited by HC-030031 and olcegepant. In pial arteries, the dilation was inhibited by TRAM-34, suggesting involvement of the KCa3.1 channel. Conclusion Na2S causes a TRPA1- and CGRP-dependent dilation of dural arteries and a KCa3.1 channel-dependent dilation of pial arteries in rats.


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