title: Inhibitory effect of TongXie-YaoFang formula on colonic contraction in rats.
abstract: OBJECTIVE
  To investigate the pharmacological effect of TongXie-YaoFang (TXYF) formula and its underlying mechanisms.
  
  
  METHODS
  A neonatal maternal separation plus restraint stress (NMS + RS) model of diarrhea-predominant irritable bowel syndrome was developed by subjecting male Sprague-Dawley rats to daily maternal separation from postnatal days 2 to 21 plus restraint stress from days 50 to 59. Rats were randomly divided into two groups (NMS + RS and TXYF formula), and rats with no handling or separation were used as normal controls. Starting from postnatal day 60, rats were administered TXYF formula (9.84 g/100 g body weight) orally twice daily for 14 consecutive days, while the normal and NMS + RS groups were given distilled water. The distinctions of movement index (MI, area under the curve of contraction intensity/min, mg/min) and contraction frequency (CF, number of contractions/min, times/min) of isolated colonic longitudinal smooth muscle strips (CLSMs) in the three groups before and after treatment were observed with a Power Lab system. Different inhibitors were applied, and then 10(-4) mol/L acetylcholine chloride (Ach) was added to CLSMs to induce muscle contraction.
  
  
  RESULTS
  Before treatment, the MI of CLSMs in the NMS + RS and TXYF formula groups was similar and both higher than that in the normal group (545.49 ± 73.66 mg/min vs 245.76 ± 34.44 mg/min and 551.09 ± 54.29 mg/min vs 245.76 ± 34.44 mg/min, P < 0.01, respectively). After treatment, the MI in the TXYF formula group was lower than that in the NMS + RS group (261.39 ± 38.59 mg/min vs 533.9 ± 61.63 mg/min, P < 0.01). In the same way, the CF of CLSMs in the NMS + RS and TXYF formula groups was similar and both higher than that in the normal group (3.42 ± 0.25 times/min and 3.31 ± 0.21 vs 1.1 ± 0.17 times/min, P < 0.01) before treatment. After treatment, the CF in the TXYF formula group was lower than that in the NMS + RS group (1.42 ± 0.87 times/min vs 3.11 ± 0.82 times/min, P < 0.01) and similar to that in the normal group (1.42 ± 0.87 times/min vs 1.09 ± 0.13 times/min). When 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride and 4-aminopyridine were added to the bath and equilibrated for 30 min, respectively, and 10(-4) mol/L Ach was added to CLSMs to induce muscle contraction, MI of the CLSMs in the TXYF formula group was lower than that in the normal group (666 ± 36.32 mg/min vs 747.77 ± 49.47 mg/min, and 686.53 ± 39.17 mg/min vs 750.45 ± 29.39 mg/min; P < 0.01, respectively). The MI of CLSMs in the TXYF formula group was lower than that in the normal group after treatment with nifedipine (689.48 ± 30.84 mg/min vs 741.65 ± 32.41 mg/min; P < 0.05).
  
  
  CONCLUSIONS
  TXYF formula inhibits colon contraction in rats. This may be related to activation of specific potassium channels and inhibition of extracellular calcium internal flow.
authors.affiliation: Cheng Yang, Sheng-Sheng Zhang, Zheng-Fang Wang, Lu-Qing Zhao, Digestive Disease Diagnosis and Treatment Center, Beijing Chinese Medicine Hospital, Capital Medical University, Beijing 100010, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.affiliation: Cheng Yang, Sheng-Sheng Zhang, Zheng-Fang Wang, Lu-Qing Zhao, Digestive Disease Diagnosis and Treatment Center, Beijing Chinese Medicine Hospital, Capital Medical University, Beijing 100010, China.
authors.forename: Sheng-Sheng
authors.initials: SS
authors.lastname: Zhang
authors.affiliation: Cheng Yang, Sheng-Sheng Zhang, Zheng-Fang Wang, Lu-Qing Zhao, Digestive Disease Diagnosis and Treatment Center, Beijing Chinese Medicine Hospital, Capital Medical University, Beijing 100010, China.
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Li
authors.affiliation: Cheng Yang, Sheng-Sheng Zhang, Zheng-Fang Wang, Lu-Qing Zhao, Digestive Disease Diagnosis and Treatment Center, Beijing Chinese Medicine Hospital, Capital Medical University, Beijing 100010, China.
authors.forename: Zheng-Fang
authors.initials: ZF
authors.lastname: Wang
authors.affiliation: Cheng Yang, Sheng-Sheng Zhang, Zheng-Fang Wang, Lu-Qing Zhao, Digestive Disease Diagnosis and Treatment Center, Beijing Chinese Medicine Hospital, Capital Medical University, Beijing 100010, China.
authors.forename: Lu-Qing
authors.initials: LQ
authors.lastname: Zhao
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D000930:Antidiarrheals / Q000494:pharmacology*; D001010:Anxiety, Separation / Q000150:complications; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D003967:Diarrhea / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology / Q000523:psychology; D004195:Disease Models, Animal; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007103:Immobilization; D043183:Irritable Bowel Syndrome / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology / Q000523:psychology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D015221:Potassium Channels / Q000819:agonists / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000930:Antidiarrheals; D015220:Calcium Channels; D004365:Drugs, Chinese Herbal; D015221:Potassium Channels; C000601593:tongxie-yaofang
keywords: Colonic longitudinal smooth muscle; Herbal medicine; Irritable bowel syndrome; Neonatal maternal separation; Potassium channel