title: TRPM8 protein localization in trigeminal ganglion and taste papillae.
abstract: TRPM8 is a TRP family cation channel which can be activated by cold stimuli or l-menthol. However, TRPM8 protein localization of nerve terminals in sensory organs remains unknown. Here we generated an antibody against TRPM8 and analyzed TRPM8 protein localization in trigeminal ganglia (TG) and in sensory nerve fibers in the tongue. TRPM8 immunoreactivity was detected in a subset of neurons with a small diameter in TG and in nerve fibers in the tongue. TRPM8-immunoreactive nerve fibers were rich in fungiform papillae, but sparse in foliate and circumvallate papillae. The TRPM8-immunoreactive nerve fibers reached the outer epithelial layer in each papilla, while no TRPM8-immunoreactive nerve fibers penetrated into taste buds. Double labeling analysis revealed that TRPM8 immunoreactivity was co-expressed with a part of TRPV1 or CGRP-immunoreactive neurons in TG. However, TRPM8 immunoreactivity was not observed in TRPV1- or CGRP-positive nerve fibers in fungiform, foliate, and circumvallate papillae. These results suggest that TRPM8 protein is present in sensory lingual nerve fibers mainly projected from TG and might work as cold and l-menthol receptors on tongue.
authors.affiliation: Division of Biological Information, Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Abe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosokawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Okazawa
authors.forename: Mikako
authors.initials: M
authors.lastname: Kandachi
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Sawada
authors.forename: Keiji
authors.initials: K
authors.lastname: Yamanaka
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsumura
authors.forename: Shigeo
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western / Q000379:methods; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002460:Cell Line; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D009363:Neoplasm Proteins / Q000378:metabolism*; D016900:Neurofilament Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050053:TRPM Cation Channels; D050916:TRPV Cation Channels; D013650:Taste Buds / Q000378:metabolism*; D014059:Tongue / Q000166:cytology* / Q000378:metabolism; D014162:Transfection / Q000379:methods; D012668:Trigeminal Ganglion / Q000166:cytology / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase / Q000378:metabolism
chemical_list: D007473:Ion Channels; D009363:Neoplasm Proteins; D016900:Neurofilament Proteins; D016271:Proto-Oncogene Proteins c-myc; D050053:TRPM Cation Channels; C425966:TRPM8 protein, human; D050916:TRPV Cation Channels; C498947:Trpm8 protein, rat; C493922:Trpv1 protein, rat; C051774:neurofilament protein H; C489034:UCHL1 protein, rat; D043222:Ubiquitin Thiolesterase; D015740:Calcitonin Gene-Related Peptide