Expression of Transient Receptor Potential Ankyrin 1 in Human Dental Pulp

• Published in: Journal of endodontics Vol. 38; no. 8; pp. 1087 - 1092
• Main Authors: Kim, Yun Sook, PhD, Jung, Hoon Kap, DDS, Kwon, Tae Kyung, DDS, Kim, Chin Soo, DDS, PhD, Cho, Jin Hyun, DDS, PhD, Ahn, Dong Kuk, DDS, PhD, Bae, Yong Chul, DDS, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2012
• Subjects: Adolescent; Axons - ultrastructure; Calcium Channels - analysis; Cell Membrane - ultrastructure; Cold hypersensitivity; Cold Temperature - adverse effects; dental pulp; Dental Pulp - innervation; Dentin Sensitivity - physiopathology; Dentistry; Endocrinology & Metabolism; Fluorescent Antibody Technique; Humans; Immunohistochemistry; inflammation; Male; Microscopy, Confocal; Microscopy, Electron; Microscopy, Fluorescence; Nav1.8; NAV1.8 Voltage-Gated Sodium Channel - analysis; Nerve Fibers, Unmyelinated - ultrastructure; Nerve Tissue Proteins - analysis; Neurofilament Proteins - analysis; nociception; Nociception - physiology; Odontoblasts - cytology; Pulpitis - pathology; Transient Receptor Potential Channels - analysis; TRPA1; TRPA1 Cation Channel; Young Adult; Cold hypersensitivity; TRPA1; inflammation; dental pulp; nociception; immunohistochemistry; Nav1.8
• ISSN: 0099-2399; 1878-3554
• DOI: 10.1016/j.joen.2012.04.024

Abstract Introduction Transient receptor potential ankyrin 1 (TRPA1) is activated by noxious cold (<17°C) and contributes to cold and mechanical hypersensitivity after inflammation and nerve injury. Methods To investigate whether TRPA1 is involved in the mediation of nociception, including noxious cold and cold hypersensitivity in teeth, we examined the expression of TRPA1 and sodium channel Nav1.8 in human dental pulp using fluorescent and electron microscopic immunocytochemistry. Results TRPA1 was expressed in a large number of axons branching extensively in the peripheral pulp and in a few axons within the nerve bundles in the core of the coronal pulp and in the radicular pulp. Under electron microscopy, TRPA1 immunoreactivity was typically localized near the plasma membrane of unmyelinated axons in the peripheral pulp, suggesting that in these axons it may act as a functional receptor. The proportion of axons expressing TRPA1 in neurofilament 200–positive axons significantly increased in the painful pulp compared with the normal pulp. TRPA1 was also densely expressed in the processes and the cell body of odontoblasts. A large number of axons coexpressed TRPA1 and Nav1.8. Conclusions These findings support the notion that TRPA1 is involved in the perception of noxious cold and cold hypersensitivity in human dental pulp and that TRPA1-mediated nociception is primarily mediated by axons and odontoblasts in the peripheral pulp.