title: Sensitivities of human jejunum, ileum, proximal colon, and gallbladder to cholecystokinin octapeptide.
abstract: We compared in humans simultaneous motor responses of the jejunum, ileum, proximal colon, and gallbladder (GB) to intravenous cholecystokinin octapeptide (CCK-OP). To gauge the physiological relevance of the doses of CCK-OP, intestinal motility and GB contraction were also quantified after a fatty meal. Eight healthy volunteers participated in both experiments. Six graded, 30-min intravenous infusions had a mean range of 2.2 to 73.2 pmol X kg-1 X h-1 of CCK-OP; these spanned from subphysiological (negligible contraction of GB) to pharmacological (producing intestinal symptoms and a 70-99% contraction of GB) levels. CCK-OP inhibited interdigestive cycles of motility, though in some persons fasting patterns persisted with doses of CCK-OP, which produced up to 50% reduction in GB volume. Motility indices of the ileum and proximal colon responded to CCK-OP by decreasing initially but then increasing with larger doses; motility of the jejunum increased gradually at all doses. Judged by the gallbladder's response to food (reduction in volume down from 74 to 29% of original volume), the physiological range of infused CCK-OP was approximately 5-16 pmol X kg-1 X h-1. Within this range of doses of CCK-OP, motility of the jejunum increased, whereas motility of the proximal colon was reduced. These data are consistent with CCK being a "physiological" mediator of intestinal motility in humans; responses of the intestine to the peptide appear to vary regionally.
mesh_terms: D000328:Adult; D003106:Colon / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004435:Eating; D005260:Female; D005704:Gallbladder / Q000187:drug effects*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006801:Humans; D007082:Ileum / Q000187:drug effects*; D007583:Jejunum / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D012844:Sincalide / Q000494:pharmacology*
chemical_list: D012844:Sincalide