Effect of Electroacupuncture at Different Acupoints on the Expression of NMDA Receptors in ACC and Colon in IBS Rats.

OBJECTIVE: To observe the effects of electroacupuncture (EA) at different acupoints on the expression of N-methyl-D-aspartate receptor (NMDA receptor ) and behaviors in irritable bowel syndrome (IBS) rats. METHODS: Wistar rats were randomly divided into blank control group (blank group, n=10) and model preparation group (n=50); experimental rat model of IBS was established by the "neonatal maternal separation and acetic acid enema" combined with "colorectal distension stimulation" method. A total of 50 IBS rats were randomly assigned to five groups of 10 each: model group, Yintang (GV29) group, Neiguan (PC6) group, Tianshu (ST25) group, and Zusanli (ST36) group. Rats in four treatment groups, aged 9 weeks old, were treated with EA by HANS with a sparse-dense wave with a frequency of 2/100 Hz, current of 0.1-0.3mA, and 20 min/stimulation, every other day for a total of 5 sessions. After treatment, the abdominal visceral sensitivity was evaluated by abdominal withdrawal reflex (AWR), and the psychological and emotional behavior of rats were evaluated by the open-field test (OFT). The expression of NMDA receptors in anterior cingulate cortex (ACC) was detected by Quantitative Real-time PCR, and the positive expression of NMDA receptors in colon was detected by immunohistochemistry. RESULTS: The IBS rat's abdomen is more sensitive and irritable; NR1, NR2A, and NR2B in ACC and NR1 and NR2B in colon of rats significantly increased in the model group versus the normal group (P<0.01) and were inhibited in all treatment groups (P<0.01, P<0.05). Additionally, NR2A and NR2B in ACC reduced more in GV29 group (P<0.01) than in other treatment groups (P all<0.05) compared with the model group. The expression of NR2B in colon was significantly inhibited in ST36 group (P<0.01) and inhibited in GV29 group and ST25 group (P all <0.05) compared with the model group. And the expression of NR2B in colon was more inhibited in ST36 group than in PC6 group (P<0.01). CONCLUSIONS: EA at different acupoints could obviously relieve abdominal pain and abnormal behaviors in IBS rats in different degrees of effects. The effect of abdominal pain-relief, from greatest to least, is ST25, ST36, GV29, and PC6, while the effect of relieving abnormal behaviors caused by IBS, from greatest to least, is GV29, PC6, ST36, and ST25. There are significant differences in the expressions of NMDA receptors in ACC and colon among different acupoints. This difference should be related to the location distribution and indications of acupoints.

[Effect of Electroacupuncture at "Neiguan" (PC 6) and "Tianshu" (ST 25) for Colonic Motility and D 2 Receptor in Irritable Bowel Syndrome Rats].

OBJECTIVE: To observe and compare the effects of electroacupuncture (EA) at "Tianshu" (ST 25) and "Neiguan" (PC 6) for colonic motility and the expression of colon dopamine D 2 in irritable bowel syndrome (IBS) rats, and to explore the specificity of different meridians and different acupoints. METHODS: Forty Wistar newborn rats were randomly divided into blank, model, Tianshu and Neiguan groups. Separation of mother and child and acetic acid coloclyster combined with colorectal distension were used to establish IBS model in the model, Tianshu and Neiguan groups. At the age of 9 weeks, EA at bilateral ST 25 and PC 6 were applied in the corresponding groups 5 times, once every other day. After the intervention, the Bristol fecal score, the latent period of abdominal retraction reflex and the number of contraction waves were recorded. The expression of dopamine D 2 receptor was detected by immunohistochemistry. RESULTS: Compared with the blank group, the Bristol fecal score of the model group was higher (P<0.01), the 1st contraction wave latent period was shorter (P<0.01), the number of contraction waves in 90 s increased (P<0.01), the immunoreactive expression of D 2 receptor in colon decreased (P<0.01). Compared with the model group, the Bristol fecal scores of the Tianshu and Neiguan groups decreased (P<0.01), the 1st contraction wave latent periods were longer (P<0.01), the numbers of contraction waves in 90 s decreased (P<0.01), the positive expressions of D 2 receptor in colon increased (P<0.01, P<0.05). Compared with the Tianshu group, the immunoreactive expression of D 2 receptor in the Neiguan group decreased (P<0.01). CONCLUSION: EA at ST 25 and PC 6 can improve the symptoms of colonic motility in IBS rats. The effect of EA at ST 25 is better, which indicates that different meridians and different acupoints play specific effects.

[Effect of Electroacupuncture at "Yintang" (GV 29) and "Tianshu" (ST 25) on the Ethology and the Expression of TRPV 1 Receptor in Colon of Irritable Bowel Syndrome Rats].

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=8 in 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 9 weeks old, 20 minutes, once every other day for 5 times. Latency of the 1st time contraction wave and numbers of contractive wave in 90 s were 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 1 expression 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 s were 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 1 expression in the colon (P<0.05). Compared with the model group, After EA intervention, the levels of the above-mentioned 5 indexes were significantly reversed in the GV 29 and ST 25 groups (P<0.01,P<0.05), except the number of horizontal movement in the ST 25 group (P>0.05). The expression level of TRPV 1 was significantly lower in the ST 25 group than in the GV 29 group (P<0.01). CONCLUSIONS: 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 depressive-like psychoemotional behavior of IBS rats, while ST 25 is more effective in treating abdominal pain. There is significantly different influence on TRPV 1 expression in colon between these two treatment groups, which may contribute to their different effect in pain relieving.