Influence of different anesthetic agents on the release of cholecystokinin in dogs

The purpose of this study was to investigate the effect of pentobarbital, halothane, and chloralose anesthesia on the endogenous release of cholecystokinin-33 (CCK-33) in dogs prepared with duodenal fistulas. Release of CCK-33 was induced by intraduodenal infusion of a medium-chain triglyceride (corn oil, 1 gm/kg/hr). Plasma CCK-33 concentrations were measured by means of a specific radioimmunoassay. Pentobarbital and chloralose were administered intravenously, and halothane was administered by a vaporizer (semiclosed technique), with O₂ and N₂O used as barriers. No incidence of hypotension was found with the use of these anesthetic agents. Basal concentrations of plasma CCK-33 were elevated, although not significantly, during pentobarbital or chloralose anesthesia. In conscious dogs (control study), peak plasma CCK-33 concentrations of 529 ± 53 pg/ml were measured 30 minutes after intraduodenal infusion of fat. Under pentobarbital anesthesia, peak plasma CCK-33 concentrations of 452 ± 264 pg/ml were found 80 minutes after infusion of fat. Under halothane anesthesia, fat-induced release of CCK-33 was abolished, whereas chloralose anesthesia did not influence fat-induced release of CCK-33. These findings may have implications for the design of future studies of gastrointestinal physiology. In CCK-33 studies that require anesthesia, chloralose appears to be an appropriate anesthetic agent.