Effects of Various Doses of Cholecystokinin Octapeptide and Cerulein on Antral Slow-Wave Frequency and Amplitude in Conscious Sheep

It is suspected that cholecystokinin (CCK) might affect antral slow-wave frequency and amplitude, but in sheep this problem is virtually unknown. Therefore the myoelectric activity was continuously recorded before and after intravenous administration of 0.15 M NaCl or CCK peptides in adult rams, equipped with platinum bipolar electrodes in the abomasal antrum, duodenum, and jejunum. CCK octapeptide (CCK-OP) was given to five rams at doses of 17.5, 175, or 1750 pmol/ kg and cerulein was administered to six rams at doses of 0.735, 7.35, or 73.5 pmol/kg of body weight. Each dose was infused to fasted or non-fasted animals for 30, 60, 120, or 300 s during phase 1, 2a or 2b (the less or more intense) of the migrating myoelectric complex (MMC). The 300-sec infusion of the moderate CCK-OP dose during the less intense or more intense phase 2b of the MMC increased the antral slow-wave amplitude from 79 ± 7 to 124 ± 26 μV ( p < 0.01) and from 82 ± 8 to 175 ± 40 μV ( p < 0.001), respectively. The 300-sec infusion of the highest CCK-OP dose under the same conditions increased antral slow-wave amplitude from 79 ± 6 to 121 ± 24 μV ( p < 0.05) and from 84 ± 9 to 138 ± 27 μV ( p < 0.01), respectively. Administration of the moderate dose of CCK for 120 s in the course of the less or more intense phase 2b of the MMC increased antral slow-wave frequency from 6.1 ± 0.2 to 6.6 ± 0.4 cpm (N.S.) and from 6.1 ± 0.3 to 6.8 ± 0.4 cpm ( p < 0.05), respectively. Administration of the highest dose of CCK-OP for 120 s in the course of the less or more intense phase 2b of the MMC increased the antral slow-wave frequency from 6.2 ± 0.3 to 7.2 ± 0.4 ( p < 0.05) and from 6.0 ± 0.3 to 7.8 ± 0.6 cpm ( p < 0.001), respectively. It is concluded that CCK in physiological and putatively pharmacological doses can affect the slow-wave frequency and amplitude in sheep related in part to the small-intestinal MMC phase and the intensity of the antral motor activity.