AAS ›› 2014, Vol. 45 ›› Issue (5): 610-615.doi: 10.3969/j.issn.0529-1356.2014.05.005

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Comparisons of expression of phosphorylated extracellular signal-regulated kinase in different levels of anterior cingulate cortex in the rat with neuropathic pain

FANG Fang  SHAO Xiao-mei  SHEN Zui  SUN Jing  FANG Jian-qiao*   

  1. Department of Neurobiology and Acupuncture Research,the Third Clinical Medical College,Zhejiang Chinese Medical University, Hangzhou 310053,China
  • Received:2014-05-16 Revised:2014-04-28 Online:2014-10-06 Published:2013-10-06
  • Contact: FANG Jian-qiao E-mail:fangjianqiao7532@163.com

Abstract:

Objective To observe the distribution features of phosphorylated p44/42 extracellular signal-regulated kinase(p-ERK) induced by affective pain in the anterior cingulate cortex (ACC) of the rat. Methods Twelve male SD rats were randomly divided into the control group (n=6) and spinal nerve ligation (SNL) group (n=6). The rats of the SNL group were exposed to unilateral L5 spinal nerve ligation (SNL) surgery. The behavior was examined by mechanical pain thresholds (MPTs) and the pain affect was measured using open-field test, elevated zero maze. The expressions of p-ERK in ACC (AP 3.2,2.7,2.2mm from Bregma) were detected with immunofluorescence test. Results In comparison with the control group, the unilateral mechanical pain threshold in the SNL group decreased significantly after operation. The operation also resulted in pronounced anxiety-like behavior. The p-ERK labelled cells in different levels of ACC(AP 3.2,2.7,2.2mm from Bregma) of SNL rats were (11.89±2.57),(32±4.67 ) and (17.56±2.04 ), respectively, while the control group rats were (12.44±2.16),(10±0.87 ) and (10.11±1.36). These data indicated that compared with the control group, the expressions of p-ERK in ACC(AP 2.7,2.2mm from Bregma) increased significantly in the SNL group after operation(P<0.01), besides for the level of ACC(AP 3.2mm from Bregma) (P>0.05). Conclusion The results suggest that the neuropathic pain can result in anxiety-like behavior and increased expressions of p-ERK in ACC of the rat. This change may be closely related to the expressions of p-ERK in ACC(AP 2.7,2.2mm from Bregma), but not to the level of ACC(AP 3.2mm from Bregma).

Key words: Neuropathic pain, Extracellular signal-regulated kinase, Anterior cingulate cortex, Pain related anxiety, Immunofluorescence, Rat