Objective: To investigate the effect of Mayuan Tongbian Zhitong decoction on intestinal function

defecation

intestinal neurotransmitter and aquaporin (AQP) in rats with slow transit constipation (STC)

and its potential mechanism of action. Method: Sixty male Sprague-Dawley rats were randomly divided into control group

model group

Mayuan Tongbian Zhitong decoction group (6

12

18 mg · kg-1)

and mosapride group. The model group

Maoyuan Tongbian Zhitong decoction group and Mosapride group were orally given diphenoxylate suspension 10 mg · kg-1 · d-1 for successively 14 d

so as to establish the STC model. After the model was established

the drug groups were respectively given the corresponding drugs

while control group and model group were given the equal volume of 0.9% NaCl solution for successively 14 days. The amount of feces and water content in each group before and during modeling and during treatment were measured. The carbon advancing rate of rats in each group was calculated; the contents of nitric oxide (NO) and nitric oxide synthase (NOS) in the colon tissues of rats in each group were detected by enzyme-linked immunosorbent assay (ELISA). Western blot was used to detect the expressions of Aquaporin 1

3

4 and 8 (AQP1

3

4 and 8) in the colon tissues of rats in each group. Result: Compared with the control group

the carbon advancing rate

defecation and fecal water content in model group was decreased (P<0.05); compared with model group

Mayuan Tongtong Zhitong decoction group and mosapride group's carbon acceleration rate and defecation and fecal water content were increased in a dose-dependent manner (P<0.05); compared with the control group

the content of NO and NOS in colon in the model group were increased (P<0.05); compared with model group

the content of NO and NOS in colon of Maoyuan Tongbian Zhitong decoction group and mosapride group were decreased in a dose-dependent manner (P<0.05). Compared with the control group

the expressions of AQP1

3

4 and 8 in the model group were significantly increased (P<0.05). Compared with the model group

the expressions of AQP1

3

4 and 8 in Mayuan Zhitong Zhitong decoction group and Mosapride group were decreased in a dose-dependent manner (P<0.05). Conclusion: Mayuan Tongbian Zhitong decoction can improve intestinal function

defecation and fecal water content in STC rats. The mechanism may be related to the decrease of the content of NO and NOS in colon and the expressions of AQP1

3

4 and 8.