Capsaicin attenuates suppression of sham feeding induced by intestinal nutrients.
Satiety appears to be mediated in part by neurally transmitted signals from the gastrointestinal tract. Capsaicin is a neurotoxin that selectively destroys small unmyelinated primary sensory neurons including some of those innervating the abdominal viscera. Therefore, we examined suppression of sham feeding induced by cholecystokinin octapeptide (CCK-8) or intraintestinal nutrient infusions in capsaicin-treated rats. Suppression of sham feeding induced by CCK-8 was significantly attenuated in rats treated with capsaicin. Suppression of sham feeding induced by intraintestinal infusions of maltose, oleic acid, or L-phenylalanine was also attenuated in capsaicin-treated rats. In contrast, capsaicin treatment did not attenuate the suppression of sham feeding induced by intraintestinal casein hydrolysate (mixed amino acids). Intraintestinal infusions of octanoic acid or D-phenylalanine solutions did not significantly suppress sham feeding in either vehicle- or capsaicin-treated rats. These results indicate that the suppression of feeding by some intestinal stimuli may be mediated by nutrient or peptide-sensitive visceral afferent neurons that are sensitive to damage or destruction by capsaicin.
D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D004750:Enteral Nutrition; D005247:Feeding Behavior / Q000187:drug effects; D007421:Intestine, Small / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012527:Satiation / Q000187:drug effects*; D012844:Sincalide / Q000494:pharmacology
D012844:Sincalide; D002211:Capsaicin