Veterinary Archives, Vol. 80 No. 3, 2010.
Original scientific paper
Stimulatory and inhibitory actions of cholecystokinin octapeptide on myoelectric activity of ovine duodenum
Krzysztof W. Romański
; Laboratory of Clinical Physiology, Department of Animal Biostructure and Physiology, Veterinary School, University of Environmental and Life Sciences, Wrocław, Poland
Abstract
Cholecystokinin (CCK) affects the intestinal motility but the character of hormone-evoked alterations is not clear. The aim of this study was to examine precisely the effects of CCK-octapeptide (CCK-OP) on duodenal myoelectric activity in non-fasted sheep in the course of chronic experiments. In fifi ve rams the bipolar platinum electrodes were surgically attached to the wall of the duodenal bulb, the distal duodenum and jejunum. Strain gauge force transducer was mounted near the duodenal electrode to verify the myoelectric recordings. During continuous myoelectrical recordings, 0.15 M NaCl or CCK-OP was administered intravenously. Slow injections of CCK-OP at the doses of 20 (over 30 s), 200 (over 30 or 60 s), and 2000 (over 30, 60, or 120 s) ng/kg of body weight were each administered in the course of duodenal phase 1, 2a, or 2b of the migrating motor complex (MMC), i. e. 5 min after the onset of each phase. Injections of the smallest dose of CCK-OP exerted a slight and mostly not signififi cant effect on the duodenal bulb and the duodenal myoelectric activity index (MAI) values. In the duodenal bulb, the effects of CCK-OP on myoelectric activity were dose-dependent and closely related to the phase of the MMC. In the duodenum, the higher doses of the hormone evoked short stimulatory followed by longer inhibitory biphasic effects on MAI. These effects were inversely related to the duration of hormone injection. Infusions of hormone at the higher doses caused less pronounced biphasic effect. It is concluded that CCK evokes stimulatory and inhibitory (biphasic) physiological effect on duodenal motility in non-fasted sheep.
Keywords
sheep; duodenal bulb; duodenum; myoelectric and motor activity; cholecystokinin octapeptide; migrating myoelectric complex
Hrčak ID:
58450
URI
Publication date:
16.6.2010.
Visits: 1.757 *