Objective To observe the ethology and expression of transient receptor potential vanilloid-1(TRPV 1)in colon of irritable bowel syndrome(IBS)rats treated by electroacupuncture(EA)at"Yintang"(GV 29)and"Tianshu"(ST 25)

so as to explore the different effectiveness of different acupoints and its related mechanism underlying improvement of the symptoms of somatopsychic illness.Methods Thirty-two neonatal Wistar rats were randomly divided into blank control group

model group

Yintang(GV 29)group

and Tianshu(ST 25)group(n=8in each group).IBS model was established by neonatal maternal separation and acetic acid enema combined with colon and rectum expansion stimulation.Rats of the GV 29 and ST 25 groups were given EA treatment at age of 9weeks old

20 minutes

once every other day for 5times.Latency of the 1st time contraction wave and numbers of contractive wave in 90 swere recorded to evaluate abdominal visceral sensitivity by abdominal withdrawal reflex.Horizontal and vertical movements were observed to assess the emotional and psychological behavior of rats by open field test.TRPV 1expression in colon was detected by immunohistochemistry method.Results Compared with the black control group

latency of the 1st time contractive wave was significantly shortened and the wave numbers in 90 swere increased significantly in the model group(P<0.01)

while the numbers of vertical and horizontal movements were also significantly reduced(P<0.01)

accompanied with increased TRPV 1expression in the colon(P<0.05).Compared with the model group

After EA intervention

the levels of the above-mentioned 5indexes were significantly reversed in the GV 29 and ST 25groups(P<0.01

P<0.05)

except the number of horizontal movement in the ST 25group(P>0.05).The expression level of TRPV 1was significantly lower in the ST 25 group than in the GV 29group(P<0.01).Conclusion EA at GV 29 and ST 25 can alleviate the abdominal pain and improve the mental and emotional disorders in IBS rats.GV 29 has a better effect on relieving the depressivelike psychoemotional behavior of IBS rats

while ST 25 is more effective in treating abdominal pain.There is significantly different influence on TRPV 1expression in colon between these two treatment groups

which may contribute to their different effect in pain relieving.