Role of cholecystokinin in the gastric motor response to a meal in horses.
OBJECTIVE
To measure plasma cholecystokinin (CCK) activity and the effect of a CCK-1 receptor antagonist on accommodation of the proximal portion of the stomach, and subsequent gastric emptying, in horses after ingestion of high-fat or high-carbohydrate meals.


METHODS
6 healthy adult horses with gastric cannulas.


METHODS
In the first study, horses were offered a high-fat (8% fat) or a high-carbohydrate (3% fat) pelleted meal of identical volume, caloric density, and protein content. Related plasma CCK-like activity was measured by radioimmunoassay (RIA). In a separate experiment, a horse was fed a grain meal with corn oil and phenylalanine, and plasma CCK activity was assessed by bioassay. A second study evaluated the effect of a CCK-1 receptor antagonist, devazepide (0.1 mg/kg, IV), on gastric accommodation and emptying following a meal of grain supplemented with either corn oil (12.3% fat) or an isocaloric amount of glucose (2.9% fat). Gastric tone was measured by a barostat and emptying by the (13)C-octanoic acid breath test.


RESULTS
No plasma CCK-like activity was detected by RIA or bioassay before or after ingestion of meals. Preprandial devazepide did not alter the gastric accommodation response but did significantly shorten the gastric half-emptying time and time to peak breath (13)CO(2) content with the glucose-enriched meal.


CONCLUSIONS
In horses, CCK participates in regulating the gastric motor response to a meal. Compared with other species, horses may be more responsive to carbohydrate than fat. A vagovagal reflex most likely mediates this regulation, with CCK as a paracrine intermediary at the intestinal level.
Lorenzo-Figueras
Mireia
M
Island Whirl Equine Colic Research Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0136, USA.
Merritt
Alfred M
AM
D000821:Animal Feed; D000818:Animals; D002247:Carbon Isotopes / Q000032:analysis; D002766:Cholecystokinin / Q000097:blood / Q000502:physiology*; D020109:Devazepide / Q000008:administration & dosage / Q000494:pharmacology; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects / Q000502:physiology*; D006727:Hormone Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D006736:Horses / Q000502:physiology*; D007456:Iodine Isotopes / Q000032:analysis; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D011897:Random Allocation; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors; D013270:Stomach / Q000502:physiology*; D013997:Time Factors
D002247:Carbon Isotopes; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D006727:Hormone Antagonists; D007456:Iodine Isotopes; D011949:Receptors, Cholecystokinin; D002766:Cholecystokinin; D020109:Devazepide