Effect of activation of the serotoninergic system during prolonged starvation on subsequent caloric intake and macronutrient selection in the Zucker rat.
Starvation or dietary restriction are known to modify post-fasting dietary self-selection. We have examined the effects of activation of the serotoninergic system and food deprivation on macronutrient self-selection following a period of starvation. Rats were starved for 4 days and either treated or not with dl-fenfluramine or fluoxetine. Starved untreated animals showed a post-fasting anorexia and an increased preference for carbohydrate intake, even though lipids remained the preferred source of calories. Treatment with fenfluramine or fluoxetine increased post-fasting anorexia, abolished the preference for carbohydrates and decreased lipid intake. Fluoxetine, but not fenfluramine, resulted in decreased protein intake as well. Following a 2-day refeeding period ad libitum, during which the animals were not treated with drugs, the anorectic effect of fenfluramine disappeared but that of fluoxetine remained unchanged. In addition, we noted that at an equimolar dose to dl-fenfluramine (100 mumol/kg/day) fluoxetine treatment resulted in the death of all the animals in the group by the second day of refeeding; no deaths were observed in any of the other groups. In conclusion, we confirm a post-starvation anorexia and increased carbohydrate intake following long-term fasting. In addition we show that activation of the serotoninergic system abolishes the increase in carbohydrate intake and potentiates post-starving anorexia.
Duhault
J
J
Institut de Recherches Servier, Suresnes, France.
Lacour
F
F
Espinal
J
J
Rolland
Y
Y
D000818:Animals; D000855:Anorexia; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D002149:Energy Intake; D005277:Fenfluramine / Q000494:pharmacology; D005473:Fluoxetine / Q000494:pharmacology; D005518:Food Preferences; D008297:Male; D051381:Rats; D011924:Rats, Zucker; D012701:Serotonin / Q000502:physiology*; D013217:Starvation / Q000503:physiopathology*
D004040:Dietary Carbohydrates; D005473:Fluoxetine; D005277:Fenfluramine; D012701:Serotonin