Objective:To observe effects of electroacupuncture at Jiaji（EX-B

2

）on phosphorylated extracellular signal regulated kinase（ERK）and neurokinin-1（NK-1）in dorsal horn of the complete Freund’s adjuvant arthritis rat

so as to study possible mechanism of electroacupuncture analgesia from the point of view of signal conduction.Methods:Eighty Wistar adult male rats were randomly divided into normal control group

simple electroacupuncture（EA）group

model 30 min group

model 24h group

model 48 h group

EA 30min group

EA 24h group

and EA 48h group

10 rats in each group.Inflammatory pain rat model was established by injection of complete Freund’s adjuvant into left hindpaw.EA was given at bilateral L

3

～L

5

Jiaji（EX-B

2

）.The pain threshold was determined and phosphorylated ERK and NK-1 expressions in the spinal cord were detected by immunohistochemical technique.Results:The pain threshold significantly decreased（all P

<

0.01）and phosphorylated ERK in the hmolateral spinal cord significantly increased（all P

<

0.01）in the various model groups as compared with those in normal control group and simple EA group;After the treatment

pain threshold decreased in all the EA groups

but it significantly increased as compared with the same time point model group

and the phosphorylated ERK level in the homolateral spinal cord significantly decreased as compared with that of the same time point model groups（P

<

0.01）.The NK-1 receptor expression in the homolateral spinal cord in the model 24h group and the EA 24h group significant increased as compared with those in the normal control group and in the simple EA group（P

<

0.05 or P

<

0.01）.Conclusion:EA at Jiaji（EX-B

2

）can significantly alleviate inflammatory pain and increase pain threshold in the adjuvant arthritis rat

and ERK is possibly an important signal conduction molecular in EA analgesia

which can play an important role in inflammatory pain sensitivity formation and EA analgesia through activation of phosphorylation and regulation on NK-1 expression.