Capsaicin attenuates feeding suppression but not reinforcement by intestinal nutrients. 1996

F Lucas, and A Sclafani
Department of Psychology, Brooklyn College New York 11210, USA.

During and after a meal, the presence of nutrients in the intestine can be rapidly detected and signaled to the brain via visceral afferents. Intestinal infusions of carbohydrate and fat suppress food intake, and this satiety action is inhibited by capsaicin, a neurotoxin that produces a partial visceral deafferentation. This study determined if the postingestive reinforcing action of nutrients is also suppressed by capsaicin treatment. Food-restricted control and capsaicin-treated rats were trained to drink a flavored solution paired with intraduodenal infusions of carbohydrate (Polycose solution) on some days and, on other days, a differently flavored solution paired with intraduodenal water infusions. In a choice test, both groups displayed a strong preference for the Polycose-paired flavor. In a subsequent satiety test, however, intraduodenal Polycose suppressed sucrose sham feeding in the controls but not in capsaicin-treated rats. The same rats were next trained to associate new flavors with intraduodenal fat (corn oil emulsion) and intraduodenal water infusions. During training, oil infusions reduced oral intakes in the controls much more than in the capsaicin-treated rats. Both groups reliably preferred the oil-paired flavor in the subsequent choice test. These results indicate that, unlike the satiating effect of intestinal carbohydrate and fat, the reinforcing actions of these nutrients are not mediated by capsaicin-sensitive visceral afferents. The data also imply that the postingestive reinforcement produced by nutrients is not dependent on the nutrients' satiating quality.

UI MeSH Term Description Entries
D007422 Intestines The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE. Intestine
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D012054 Reinforcement, Psychology The strengthening of a conditioned response. Negative Reinforcement,Positive Reinforcement,Psychological Reinforcement,Reinforcement (Psychology),Negative Reinforcements,Positive Reinforcements,Psychological Reinforcements,Psychology Reinforcement,Psychology Reinforcements,Reinforcement, Negative,Reinforcement, Positive,Reinforcement, Psychological,Reinforcements (Psychology),Reinforcements, Negative,Reinforcements, Positive,Reinforcements, Psychological,Reinforcements, Psychology
D002211 Capsaicin An alkylamide found in CAPSICUM that acts at TRPV CATION CHANNELS. 8-Methyl-N-Vanillyl-6-Nonenamide,Antiphlogistine Rub A-535 Capsaicin,Axsain,Capsaicine,Capsicum Farmaya,Capsidol,Capsin,Capzasin,Gelcen,Katrum,NGX-4010,Zacin,Zostrix,8 Methyl N Vanillyl 6 Nonenamide,NGX 4010,NGX4010
D004040 Dietary Carbohydrates Carbohydrates present in food comprising digestible sugars and starches and indigestible cellulose and other dietary fibers. The former are the major source of energy. The sugars are in beet and cane sugar, fruits, honey, sweet corn, corn syrup, milk and milk products, etc.; the starches are in cereal grains, legumes (FABACEAE), tubers, etc. (From Claudio & Lagua, Nutrition and Diet Therapy Dictionary, 3d ed, p32, p277) Carbohydrates, Dietary,Carbohydrate, Dietary,Dietary Carbohydrate
D004041 Dietary Fats Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados. Fats, Dietary,Dietary Fat,Fat, Dietary
D004386 Duodenum The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers. Duodenums
D004435 Eating The consumption of edible substances. Dietary Intake,Feed Intake,Food Intake,Macronutrient Intake,Micronutrient Intake,Nutrient Intake,Nutritional Intake,Ingestion,Dietary Intakes,Feed Intakes,Intake, Dietary,Intake, Feed,Intake, Food,Intake, Macronutrient,Intake, Micronutrient,Intake, Nutrient,Intake, Nutritional,Macronutrient Intakes,Micronutrient Intakes,Nutrient Intakes,Nutritional Intakes
D005260 Female Females
D005518 Food Preferences The selection of one food over another. Food Selection,Food Preference,Food Selections,Preference, Food,Preferences, Food,Selection, Food,Selections, Food

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