Morphologic Change of Parvalbumin-positive Myelinated Axons in the Human Dental Pulp

Quantitative ultrastructural analysis of fibers expressing parvalbumin, calretinin, calbindin D‐28k, stage specific embryonic antigen‐4, and phosphorylated neurofilament 200 in the peripheral sensory root of the rat trigeminal ganglion

“…However, they also raise the possibility that PV, CR, and CB can be expressed in nociceptive neurons. This has been suggested previously by at least two lines of evidence, (1) some PV+, CR+, and CB+ neurons in the TG and DRG and their peripheral axons coexpress the markers for nociceptive neurons IB4, SP, CGRP, or tachykinin (Carr, Yamamoto, Karmy, Baimbridge, & Nagy, 1989;Chiu et al, 2014;Ichikawa et al, 1993bIchikawa et al, -1995Li et al, 2005), and (2) PV, CR, and CB are expressed in sensory neurons innervating the dental pulp, which is innervated primarily by nociceptors (Ichikawa et al, 1994a(Ichikawa et al, -1996Kim, Park, Choi, Lee, & Bae, 2017), and in part by low-threshold mechanoreceptors activated by non-noxious stimuli (Byers & Närhi, 1999: Fried et al, 2011. The majority of TG neurons at the origin of PV+, CR+, and CB+ large myelinated fibers are likely LTM neurons rather than proprioceptive neurons innervating muscles since the somata of the proprioceptive neurons innervating masticatory muscles are located in the trigeminal mesencephalic nucleus (Nomura & Mizuno, 1985;Paik et al, 2012;Shigenaga, Yoshida, Mitsuhiro, Doe, & Suemune, 1988), and the TG contains a small number of proprioceptive neurons innervating extraocular muscles (Porter, Guthrie, & Sparks, 1983).…”

Morphological foundations of pain processing in dental pulp

“…It was shown that virtually all axons in the sensory roots of the TG that are immunopositive for parvalbumin (PV+) are myelinated [21]. A study using PV as a marker for myelinated axons indicated that the parent myelinated axons innervating human dental pulp undergo significant morphological changes during their peripheral course before and after they enter the dental pulp [3]. Thus, about 66%, 79%, and 99% of the PV+ axons in the radicular pulp, the core of the coronal pulp, and the peripheral pulp, respectively, were unmyelinated ( Fig.…”

“…Dental pulp is a useful organ for studying the peripheral mechanisms of pain. Activation of the pulpal nerve by many types of stimuli, including chemical, mechanical, and thermal stimuli, primarily induces painful sensations even though it is innervated by various types of sensory nerve fibers, including Aβ large myelinated fibers [1][2][3]. Elucidation of the types and properties of nerve fibers innervating dental pulp and of the sensory receptors and ion channels expressed in each type of pulpal nerve fiber is crucial for understanding the peripheral mechanisms of dental pain.…”

“…Frequency (mean ± S.D., %) of PV-immunopositive myelinated and unmyelinated axons in the root (radicular) pulp, the core of the coronal pulp, and the peripheral pulp of human upper premolars. Data are modified from the study by Kim et al[3].…”

Synaptic coupling of inner ear sensory cells is controlled by brevican-based extracellular matrix baskets resembling perineuronal nets

“…Primary antibodies were detected by fluorescent secondary antibodies (Cy2- or Cy3-conjugated, 1:1000; Cy5 conjugated, 1:800, DIANOVA; Alexa488-conjugated 1:1000, Invitrogen), and nuclei were stained using DAPI (1:2000, Sigma-Aldrich). The applied antibodies were either well characterized elsewhere (anti-aggrecan AB1031: [ 47 ]; anti-HAPLN4: [ 62 ]; anti-HAPLN1: [ 1 ]; anti-brevican: [ 27 ]; anti-neurocan: [ 63 ]; anti-vGlut3: [ 21 ]; Ca v 1.3: [ 32 ]; anti-CtBP2: [ 64 ]; anti-GluR2/3: [ 65 ]; anti-PSD-95: [ 32 ]; anti-GluR4: [ 66 ]; anti-MBP: [ 67 ]; anti-SMI32: [ 68 ]) or specificity was confirmed by using specific knockout lines ( bcan −/− , acan +/− , ncan −/− , hapln1 −/− , tenR −/− ).…”