Pharmacological effects of oxytocin on gastric emptying and intestinal transit of a non-nutritive liquid meal in female rats.
The effects of oxytocin (OT) on gastric emptying, gastrointestinal transit, and plasma levels of cholecystokinin (CCK) were studied in female rats. Gastrointestinal motility was assessed in rats 15 min after intragastric instillation of a test meal containing charcoal and Na(2)(51)CrO(4). Gastric emptying was determined by measuring the amount of radiolabeled chromium contained in the small intestine as a percentage of the initial amount received. Gastrointestinal transit was evaluated by calculating the geometric center of distribution of the radiolabeled marker. Blood samples were collected for CCK radioimmunoassay. After administration of OT (0.2-0.8 mg/kg), gastric emptying and gastrointestinal transit were inhibited, whereas the plasma concentration of CCK was increased in a dose-dependent manner. Atosiban, an oxytocin receptor antagonist, effectively attenuated the OT- induced inhibition of gastric emptying and gastrointestinal transit. However, administration of atosiban alone had no effect on gastric emptying and gastrointestinal transit. The selective CCK(1) receptor antagonists, devazepide and lorglumide, effectively attenuated the OT-induced inhibition of gastric emptying and gastrointestinal transit. L-365, 260, a selective CCK(2) receptor antagonist, did not alter the OT-induced inhibition of gastric emptying and gastrointestinal transit. These results suggest that OT inhibits gastric emptying and gastrointestinal transit in female rats via a mechanism involving CCK stimulation and CCK(1) receptor activation.
Wu
Chiu-Lung
CL
Department of Physiology, School of Medicine, National Yang-Ming University, Shih-Pai, Taipei 11221, Taiwan, Republic of China.
Hung
Chen-Road
CR
Chang
Full-Young
FY
Pau
K-Y Francis
KY
Wang
Paulus S
PS
D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002766:Cholecystokinin / Q000037:antagonists & inhibitors / Q000097:blood; D020109:Devazepide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects* / Q000502:physiology; D005765:Gastrointestinal Agents / Q000494:pharmacology*; D005772:Gastrointestinal Transit / Q000187:drug effects* / Q000502:physiology; D006727:Hormone Antagonists / Q000494:pharmacology; D010121:Oxytocin / Q000494:pharmacology*; D010671:Phenylurea Compounds / Q000494:pharmacology; D011377:Proglumide / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors / Q000502:physiology; D014668:Vasotocin / Q000031:analogs & derivatives* / Q000494:pharmacology
D001570:Benzodiazepinones; D005765:Gastrointestinal Agents; D006727:Hormone Antagonists; D010671:Phenylurea Compounds; D011949:Receptors, Cholecystokinin; C047046:atosiban; C058121:L 365260; D010121:Oxytocin; D002766:Cholecystokinin; D011377:Proglumide; D020109:Devazepide; C048181:lorglumide; D014668:Vasotocin