Distribution of transient receptor potential melastatin-8-containing nerve fibers in rat oral and craniofacial structures

Ann Anat. 2015 Sep;201:1-5. doi: 10.1016/j.aanat.2015.04.003. Epub 2015 Apr 25.

Abstract

The transient receptor potential melastatin-8 (TRPM8) is a cold and menthol receptor located in the sensory ganglia. Immunohistochemistry for TRPM8 was performed on oral and craniofacial structures of the rat. TRPM8-immunoreactive (-IR) nerve fibers were detected in the oral mucous membrane. In the gingiva, TRPM8-IR nerve fibers were abundant beneath and within crestal and outer epithelia. Such nerve fibers were also common beneath and within taste buds in the incisive papilla. In addition, TRPM8-immunoreactivity was expressed by some taste bud cells in the papilla. Lips, periodontal ligaments and salivary glands as well as masticatory muscles and temporomandibular joints were mostly devoid of TRPM8-IR nerve fibers. A double immunofluorescence study indicated different distribution patterns of nerve fibers containing TRPM8 and calcitonin gene-related peptide in oral and craniofacial tissues. Retrograde tracing method also indicated that TRPM8-IR nerve fibers in the gingiva and incisive papilla originate from small sensory neurons in the trigeminal ganglion. TRPM8 may be associated with cool, cold nociceptive (<around 25°C) and chemoreceptive transmission in the oral mucosa.

Keywords: Gingiva; Immunohistochemistry; Incisive papilla; Rat; Transient receptor potential melastatin-8; Trigeminal ganglion.

MeSH terms

  • Animals
  • Face
  • Gingiva / innervation
  • Gingiva / metabolism
  • Head
  • Lip / innervation
  • Lip / metabolism
  • Male
  • Masticatory Muscles / innervation
  • Masticatory Muscles / metabolism
  • Mouth / innervation*
  • Mouth / metabolism*
  • Nerve Fibers / metabolism*
  • Palate / innervation
  • Palate / metabolism
  • Periodontal Ligament / innervation
  • Periodontal Ligament / metabolism
  • Rats
  • Rats, Wistar
  • Receptors, Calcitonin Gene-Related Peptide / metabolism
  • TRPM Cation Channels / metabolism*
  • Taste Buds / metabolism
  • Temporomandibular Joint / innervation
  • Temporomandibular Joint / metabolism
  • Trigeminal Ganglion / anatomy & histology
  • Trigeminal Ganglion / metabolism

Substances

  • Crcp protein, rat
  • Receptors, Calcitonin Gene-Related Peptide
  • TRPM Cation Channels
  • Trpm8 protein, rat