title: Role of ERK1/2 activation on itch sensation induced by bradykinin B1 activation in inflamed skin.
abstract: It has previously been demonstrated that bradykinin receptor B1 (B1R) agonists evoke an itch-related scratching response in inflamed skin via the B1 receptor; however, the mechanisms responsible for this abnormal itch sensation remain unclear. Therefore, the present study utilized a complete Freund's adjuvant (CFA)-induced mouse model of inflammation to elucidate the mechanisms responsible. Over a period of 30 min, scratching behavior was quantified by the number of hind limb scratches of the area surrounding the drug injection site on the neck. Furthermore, western blot analysis was used to investigate the potential role of extracellular signal-regulated kinase (ERK) 1/2 signaling as a mediator of itch in CFA-treated mice. The results demonstrated that CFA-induced inflammation at the back of the neck is associated with sustained enhancement of ERK1/2 activation in the spinal cord. Moreover, B1R agonist treatment resulted in increased expression of phosphorylated ERK1/2 in the spinal cord, which peaked at 45 min. Consistent with these findings, inhibition of either mitogen-activated protein/ERK kinase or ERK1/2, as well as inhibition of ERK1/2 activation following inflammation, attenuated B1 receptor-mediated scratching responses to a greater extent, as compared with control mice. Collectively, the results of the present study indicated that enhanced and persistent ERK1/2 activation in the spinal cord may be required to induce a scratching response to B1R agonists following CFA-induced inflammation.
authors.affiliation: Postgraduate Institute, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China; Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China.
authors.forename: Yuanzhen
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Postgraduate Institute, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China; Division of Anesthesiology, Department of Cardiovascular Surgery, Guangdong Institute of Cardiovascular Diseases, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China.
authors.forename: Shuyan
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Postgraduate Institute, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China; Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China.
authors.forename: Yuying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Postgraduate Institute, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China; Division of Anesthesiology, Department of Cardiovascular Surgery, Guangdong Institute of Cardiovascular Diseases, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China.
authors.forename: Jialing
authors.initials: J
authors.lastname: Xiong
authors.affiliation: Postgraduate Institute, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China; Division of Anesthesiology, Department of Cardiovascular Surgery, Guangdong Institute of Cardiovascular Diseases, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China.
authors.forename: Jiexian
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Anesthesiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China.
authors.forename: Wenjin
authors.initials: W
authors.lastname: Ji
keywords: extracellular signal-regulated kinase 1/2; inflammation; itch; kinin B1 receptor agonist; spinal cord