2013 Fiscal Year Final Research Report

Basic research of orofacial neuropathic pain mechanisms for novel therapy

Research Project

Project/Area Number	24792259
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Surgical dentistry
Research Institution	Nihon University
Principal Investigator	SUZUKI Ikuko 日本大学, 歯学部, 研究員 (60459906)
Project Period (FY)	2012-04-01 – 2014-03-31
Keywords	神経障害性疼痛 / 機械痛覚過敏 / 熱痛覚過敏 / MAPキナーゼ / 三叉神経脊髄路核尾側亜核
Research Abstract	We evaluated the involvement of the mitogen-activated protein kinase (MAPK) cascade in orofacial neuropathic pain mechanisms. The nocifensive behavior was significantly enhanced in chronic constriction nerve injury of the infraorbital nerve (ION-CCI) rat. ION-CCI rats had an increased number of phosphorylated ERK immunoreactive (pERK-IR) cells. After intrathecal administration of the MEK1 inhibitor PD98059 in ION-CCI rats, the enhanced thermal nocifensive behavior but not the mechanical nocifensive behavior were significantly reduced in ION-CCI rats. The responses of wide dynamic range neurons to noxious mechanical and thermal stimulation in ION-CCI rats were significantly depressed following i.t. administration of PD98059, whereas responses to non-noxious mechanical and thermal stimulation were not altered. The present findings suggest that pERK-IR neurons play a pivotal role in the development of thermal hypersensitivity in the face following trigeminal nerve injury.