Behavioral responses and Fos activation following orofacial formalin injection in a rodent model of Parkinson's disease

Research Project

Project/Area Number	23592988
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Surgical dentistry
Research Institution	Osaka University
Principal Investigator	NIWA Hitoshi 大阪大学, 歯学研究科(研究院), 教授 (30218250)
Co-Investigator(Kenkyū-buntansha)	SUGIMURA Mitsutaka 大阪大学, 大学院歯学研究科, 准教授 (90244954) MASAWAKI Aya 大阪大学, 歯学部附属病院, 医員 (50609659) MAEGAWA Hiroharu 大阪大学, 歯学部附属病院, 医員 (10711012)
Project Period (FY)	2011 – 2013
Project Status	Completed (Fiscal Year 2013)
Budget Amount *help	¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000) Fiscal Year 2013: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000) Fiscal Year 2012: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000) Fiscal Year 2011: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Keywords	パーキンソン病 / 口腔顔面痛 / 疼痛関連行動 / ホルマリンテスト / 痛覚 / c-Fos / ラット / 三叉神経 / c－Fos / ﾎﾙﾏﾘﾝテスト
Research Abstract	We investigated the modulation of the nociceptive stimuli from the orofacial region in Parkinson's disease (PD) model rats, which were produced by the unilateral or bilateral injection of 6-OHDA into the medial forebrain bundle. Behavioral responses to formalin injection into the upper lip and the expression of c-Fos and pERK in trigeminal spinal subnucleus caudalis (Vc) were explored. Unilateral PD rats showed increased nociceptive responses when formalin was injected ipsilaterally to the lesion. This hyperalgesic response was associated with increased c-Fos expression in Vc. When formalin was injected into contralateral side to 6-OHDA lesion, behavioral responses were reduced in 6-OHDA rats. However, the expression of pERK in Vc remained unchanged. Although the hyperalgesic response was not observed in bilateral PD rats, c-Fos expression in Vc increased. These results suggest that 6-OHDA resion causes hyperalgesic response to nociceptive stimulation from the orofacial region.