Effect of calcitonin on the interdigestive motility and on gastric and pancreatic secretion in humans

Calcitonin given in doses (0.2 and 1 MRC U/kg-1h-1) reproducing the levels observed in medullary carcinoma of the thyroid, induced the appearance of phase III type activity and reduced the duration of the IMC in the small intestine from 123 to 87 min with 0.2 MRC U kg-1h-1 and from 123 to 43 min with 1 MRC U kg-1h-1 but not in the stomach of young volunteers. This increase in phase III-like activity occurred despite a sharp reduction in motilin levels. Only the highest dose of calcitonin reduced significantly acid secretion (by more than 90%) while both doses reduced amylase secretion by respectively 65 and 71% when compared to the control levels. These changes in motility and secretion could partly explain the diarrhea observed in patients with the medullary carcinoma of the thyroid.     

Ghrelin stimulates gastric acid secretion and motility in rats

Ghrelin, a novel growth-hormone-releasing peptide, was discovered in rat and human stomach tissues. However, its physiological and pharmacological actions in the gastric function remain to be determined. Therefore, we studied the effects of rat ghrelin on gastric functions in urethane-anesthetized rats. Intravenous administrations of rat ghrelin at 0.8 to 20 microgram/kg dose-dependently increased not only gastric acid secretion measured by a lumen-perfused method, but also gastric motility measured by a miniature balloon method. The maximum response in gastric acid secretion was almost equipotent to that of histamine (3 mg/kg, i.v.). Moreover, these actions were abolished by pretreatment with either atropine (1 mg/kg, s.c.) or bilateral cervical vagotomy, but not by a histamine H(2)-receptor antagonist (famotidine, 1 mg/kg, s.c.). These results taken together suggest that ghrelin may play a physiological role in the vagal control of gastric function in rats.     

Effect of mepacrine on gastric motility in the rat

Mepacrine given orally to rats inhibits gastric motility; its blocking effect is comparable to that of chloroquine, papaverine, and drotaverine, but less expressed than that of bencyclane. Similarly as the delayed gastric emptying induced by chloroquine, the effect of mepacrine is antagonized by acetyl-beta-methylcholine in a dose-related fashion, while that of papaverine, drotaverine, and bencyclane remains unchanged after treatment with the cholinomimetic drug.     

针刺在调控胃动力作用中对Cajal细胞影响

目的:观察针刺足三里穴引起胃电活动变化以及时胃电起搏区Cajal间质细胞(interstitial cells of cajal,ICCs)的影响.方法:将大鼠随机分成足三里组、非经非穴组、非针刺对照组,观察电针后胃电的变化,采用免疫组化荧光标记的方法,同步观察针刺足三里穴对ICCs的激活.结果:电针足三里穴可以使胃电的频率及波幅均增高;电针足三里穴能增加肌间神经丛和肌层ICCs的表达.结论:电针足三里穴对胃有明显促进作用;电针足三里穴促进胃运动的机制可能通过激活起搏胃肠动力的ICCs实现的.