Abstract
Total caloric intake and dietary self-selection of the three macronutrients protein, fat, and carbohydrate were examined in male rats maintained on a 6-h feeding schedule following the administration of the opioid antagonist naloxone HCl (0.1, 1.0, and 10.0 mg/kg IP). Total caloric intake (calculated as the sum of caloric intakes from each of the macronutrients) was decreased for up to 2 h following naloxone administration. By the end of the 6-h feeding period, however, no differences in total caloric intakes were observed as a function of naloxone injections. Examination of intakes of the individual macronutrients revealed that naloxone differentially affected fat, carbohydrate, and protein consumption. Across the 6-h feeding period, animals consumed less calories from the fat ration following all three doses of naloxone than after saline injections. Carbohydrate intake was decreased for up to 2 h following naloxone injections, but returned to control values by the end of the 6-h feeding period. Protein intake, in contrast to fat and carbohydrate intakes, did not vary as a function of naloxone administration. Results of the present experiment are contrasted with patterns of dietary self-selection observed following morphine administration.
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Marks-Kaufman, R., Kanarek, R.B. Modifications of nutrient selection induced by naloxone in rats. Psychopharmacology 74, 321–324 (1981). https://doi.org/10.1007/BF00432739
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DOI: https://doi.org/10.1007/BF00432739