Low susceptibility of stress ulcer in diabetic rats: role of cholinergic gastric motility.

The induction of gastric hemorrhage ulcer by cold restraint stress (CRS) and the changes of cholinergic gastric motilities were studied in streptozotocin (STZ)-induced diabetic (DM) rats to compare with the age-matched normoglycemic rats. After receiving cold restraint stress for 4 h, a lower of both gastric motility and hemorrhagic ulcer was found in the STZ-induced diabetic rats in a time-dependent way from 0-16 week (s) parallel with the induction of diabetes. The mucosal ulceration induced by CRS was correlated with the amplitude (r=0.8928, p<0.001) and frequency (r=0.8674, p<0.001) of gastric motility in diabetic rats. A significant (p<0.01) lowering of mucosal glutathione levels and mucus production also was observed in stressed diabetic rats. Under stress condition, the cholinergic gastric motility and mucosal lesion were markedly reduced by an intraperitoneal injection (i.p.) of atropine (1.0 mg/kg, i.p.) or bilateral vagotomy in 8-week STZ-DM rats. Otherwise, bethanechol (2.0 mg/kg, i.p.), 2-deoxy-D-glucose (135 mg/kg, i.p.) and metoclopramide (20 mg/kg, i.p.) stimulated gastric motility and aggravated mucosal lesions significantly (p<0.05). It is indicated that cholinergic gastric motility was lowered in DM rats in a manner can decrease mucosal lesion induced by CRS.