Objective: To study the relationship between the inhibitory effects of Tongxie Yaofang, a compound traditional Chinese herbal medicine, on the contraction of the colonic smooth muscle isolated from rats and calcium mobilization. Methods: By measuring the tension of the isolated colonic smooth muscle strips, the inhibitory effects of Tongxie Yaofang on the contraction induced by acetylcholine (ACh), KCl and exhausting Ca(2+) of internal calcium store were assessed respectively. Results: Tongxie Yaofang could concentration-dependently inhibit the contraction of isolated rat colonic smooth muscle strips induced by KCl and exhausting the Ca(2+) of internal calcium store. Tongxie Yaofang could also inhibit the tension of the second contractile phase induced by ACh (P<0.01, vs control), but had no influence on the first contractile phase. Conclusion: Tongxie Yaofang can inhibit the contraction of isolated rat colonic smooth muscle strips mainly by preventing the influx of extracellular Ca(2+), which may be associated with blocking voltage-dependent channel, store-operated channel and receptor-operated channel, but not by preventing the release of internal Ca(2+) from calcium store.

OBJECTIVE To investigate the pharmacodynamic effects of the Citri Grandis Exocarpium extract on anorexia model immature rats.METHODS Ten immature rats were randomly selected as the control group and given regular diet， while anorexia model was induced in the remaining 50 immature rats using the etiological simulation method. The immature model rats were divided into the model group， Jianwei xiaoshi tablet group （0.65 g/kg）， Citri Grandis Exocarpium extract low-dose， medium- dose and high-dose groups （0.5， 1.0， 2.0 g/kg）. After 14 d of continuous intragastric administration， the body mass and food intake of rats in each group were observed， and the gastric acid concentration， pepsinase activity， serum levels of gastrin （GAS）， motilin （MTL） and gastric inhibitory peptide （GIP） were measured. The histopathological changes in the gastric tissue were observed.RESULTS Compared with control group， the food intake， gastric acid concentration， pepsin activity， the levels of GAS and MTL were significantly decreased and GIP level was significantly increased in the immature rats of model group （P＜0.05）； gastric histopathological examination showed significant gastric mucosal congestion and loosening and detachment of epithelial cells. Compared with model group， all administration groups showed different degrees of improvement in the above indexes and decreased gastric histopathological damage after drug intervention.CONCLUSIONS Citri Grandis Exocarpium extract improves gastric motility and protects gastric mucosa in the immature rats by regulating the concentration of gastric acid， pepsin activity， the levels of GAS， MTL and GIP， thus improving anorexia in immature rats.