title: Differential activation of mitogen-activated protein kinases and glial cells in the trigeminal sensory nuclear complex following lingual nerve injury.
abstract: Mitogen-activated protein kinases (MAPKs) play a pivotal role in the mediation of cellular responses to a variety of signaling molecules. The current study demonstrates phosphorylation of extracellular signal-regulated kinase (ERK) and p38 MAPK in each subdivision of the trigeminal sensory nuclear complex (TSNC) following lingual nerve injury. Immunohistochemical labeling for phosphorylated ERK (p-ERK) or phosphorylated p38 (p-p38) MAPK was performed in histological sections of the brainstem. A transient increase in the immunoreactivity for p-ERK was found in each subdivision of the TSNC followed by a prolonged increase in the immunoreactivity for p-p38 MAPK after nerve injury. Double immunofluorescence labeling with cell-specific markers revealed that ERK and p38 MAPK were phosphorylated predominantly by OX-42-positive microglia or GFAP-positive astrocytes. Increased immunofluorescence labeling for OX-42 and GFAP indicated that microglia and astrocytes were activated by nerve injury in the TSNC. Activation of MAPKs and glial cells in the rostral subdivisions of the TSNC was comparable with that in the subnucleus caudalis of the trigeminal spinal tract nucleus (Vc). We conclude that differential activation of MAPKs and glial cells in the rostral subdivisions of the TSNC as well as the Vc may have a substantial role in the pathogenesis of neuropathic pain following trigeminal nerve injury.
authors.affiliation: Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Kita-ku, Okayama 700-8525, Japan. ryujit@md.okayama-u.ac.jp
authors.forename: Ryuji
authors.initials: R
authors.lastname: Terayama
authors.forename: Naoko
authors.initials: N
authors.lastname: Fujisawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yamaguchi
authors.forename: Shinji
authors.initials: S
authors.lastname: Omura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ichikawa
authors.forename: Tomosada
authors.initials: T
authors.lastname: Sugimoto
mesh_terms: D000818:Animals; D004789:Enzyme Activation / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D061222:Lingual Nerve Injuries; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009437:Neuralgia / Q000378:metabolism* / Q000503:physiopathology; D009457:Neuroglia / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014278:Trigeminal Nuclei / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D020928:Mitogen-Activated Protein Kinases