COMPOSED INFLUENCES OF THE AMPHIBIAN CHOLECYSTOKININ ANALOGUE - CERULEIN ADMINISTERED DURING VARIOUS PHASES OF THE MIGRATING MYOELECTRIC COMPLEX ON DUODENAL, JEJUNAL AND ILEAL MYOELECTRIC ACTIVITY IN SHEEP

This work was aimed to precise the character of the amphibian cholecystokinin analogue – cerulein action on duodenal, jejunal and ileal myoelectric activity in fasted and non-fasted sheep. Six adult rams with electrodes implanted to the duodenal bulb, duodenum, proximal jejunum and terminal ileum were used. The migrating myoelectric complex (MMC) duration and its phase 3 parameters were assessed during control experiments and in response to slow injections (1, 10 or 100 ng/kg) during phase 1, 2a and 2b of the duodenal MMC or infusions of cerulein (0.5 or 1.5 ng/kg/min) during the duodenal phase 2b MMC. The lowest dose of cerulein (injected within 30 s) produced no significant response. The moderate dose (injected within 30 or 60 s) and high dose (each injected within 30, 60 or 120 s) delayed the occurrence of phase 3 MMC in the duodenum, decreased duration of phase 3 and caused the arrival of various types of abnormal phases 3 MMC. The effects of cerulein infusions were similar. These changes, except the induction of abnormal phases 3 MMC were dose-dependent and were more pronounced in non-fasted than in fasted sheep, especially when cerulein was injected during phase 2a or 2b MMC than during phase 1 MMC. Changes in the ileal MMC were present but were less clear. It is concluded that cerulein participates in the control of MMC in ovine duodenojejunum and might be responsible either for the postprandial changes in MMC cycle or for the occurrence of abnormal phases 3.