Involvement of cholecystokinin receptor in the inhibition of gastric emptying by oxytocin in male rats.
The effects of oxytocin (OT) on gastric emptying and plasma levels of cholecystokinin (CCK) were studied in male rats. Gastrointestinal motility was assessed in rats 15 min after intragastric instillation of a test meal containing charcoal and Na2(51)CrO4. Gastric emptying was determined by measuring the amount of radiolabeled chromium contained in the small intestine as a percentage of the initial amount received. Blood samples were collected for OT and CCK radioimmunoassay. After administration of OT (0.2-0.8 mg x kg(-1)), gastric emptying was inhibited, whereas plasma concentrations of OT and CCK were increased in a dose-dependent manner. Atosiban, an oxytocin receptor antagonist, effectively attenuated the OT-induced inhibition of gastric emptying. However, administration of atosiban alone had no effect on gastric emptying. Devazepide (3 mg x kg(-1)), a selective CCKA receptor antagonist, effectively attenuated the OT-induced inhibition of gastric emptying. L-365, 260, a selective CCKB receptor antagonist, did not alter the OT-induced inhibition of gastric emptying. These results suggest that OT inhibits gastric emptying in male rats via a mechanism involving CCK stimulation and CCKA receptor activation.
Wu
Chiu-Lung
CL
Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, Republic of China.
Hung
Chen-Road
CR
Chang
Full-Young
FY
Pau
K-Y Francis
KY
Wang
Jui-Ling
JL
Wang
Paulus S
PS
D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D020109:Devazepide / Q000494:pharmacology; D005746:Gastric Emptying / Q000187:drug effects* / Q000502:physiology*; D006727:Hormone Antagonists / Q000494:pharmacology; D008297:Male; D009994:Osmolar Concentration; D010121:Oxytocin / Q000097:blood / Q000494:pharmacology*; D010671:Phenylurea Compounds / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011949:Receptors, Cholecystokinin / Q000502:physiology*; D014668:Vasotocin / Q000031:analogs & derivatives* / Q000494:pharmacology
D001570:Benzodiazepinones; D006727:Hormone Antagonists; D010671:Phenylurea Compounds; D011949:Receptors, Cholecystokinin; C047046:atosiban; C058121:L 365260; D010121:Oxytocin; D020109:Devazepide; D014668:Vasotocin