GASTRIC-EMPTYING IN OLETF RATS NOT EXPRESSING CCK-A RECEPTOR GENE

We have very recently demonstrated the low acidity of gastric juice an d the high susceptibility to the development of gastric ulceration in Otsuka Long-Evans Tokushima Fatty (OLETF) rats not expressing CCK-A re ceptors. In the present study, gastric emptying in this strain was exa mined and compared with control Long-Evans Tokushima Otsuka (LETO) rat s, Gastric emptying was evaluated by the phenol red method. Gastric em ptying 30 and 60 min after a liquid meal in OLETF rats was significant ly delayed compared to that in control LETO rats, Intraperitoneal inje ction of CCK-8 at a dose of 5 mu g/kg significantly inhibited gastric emptying in control LETO rats, whereas the same dose of CCK-8 failed t o inhibit gastric emptying in OLETF rats. These results suggest for th e first time that gastric emptying was suppressed in OLETF rats, We al so confirmed with this mutant that CCK delays gastric emptying through the CCK-A receptors.