title: ERK is involved in tooth-pressure-induced Fos expression in Vc neurons.
abstract: Discomfort and pain encountered during orthodontic treatment are major problems for patients, but the details of the underlying neural processes and molecular mechanisms are not well-understood. Here we show that noxious tooth mechanical pressure induced by orthodontic elastics resulted in a rapid and transient activation of extracellular signal-regulated protein kinase (ERK) in the trigeminal spinal subnucleus interpolaris and caudalis transition zone (Vi/Vc), trigeminal spinal subnucleus caudalis (Vc), and upper cervical spinal cord (Vc/C2). The phosphorylated ERK (pERK) was observed in neurons but not in astroglia and microglia. Single-plane scanning analysis indicated that the pERK was localized to the nucleus of Vc neurons. In addition, the tooth mechanical pressure led to Fos expression in the pERK-positive Vc neurons that would be suppressed by intrathecal administration of an MEK1/2 inhibitor (PD98059). Taken together, these findings suggest that activation of the ERK signaling cascade following noxious mechanical pressure on the teeth regulates Fos expression in Vc neurons and may thereby contribute to pain associated with orthodontic treatment.
authors.affiliation: Department of Orthodontics, Nihon University School of Dentistry, Chiyoda, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hasegawa
authors.forename: M
authors.initials: M
authors.lastname: Kondo
authors.forename: I
authors.initials: I
authors.lastname: Suzuki
authors.forename: N
authors.initials: N
authors.lastname: Shimizu
authors.forename: B J
authors.initials: BJ
authors.lastname: Sessle
authors.forename: K
authors.initials: K
authors.lastname: Iwata
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000378:metabolism*; D010146:Pain / Q000378:metabolism; D011312:Pressure; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques; D014278:Trigeminal Nuclei / Q000166:cytology / Q000378:metabolism*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D048049:Extracellular Signal-Regulated MAP Kinases