, Volume 74, Issue 4, pp 321–324

Modifications of nutrient selection induced by naloxone in rats

  • Robin Marks-Kaufman
  • Robin B. Kanarek
Original Investigations


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.

Key words

Dietary self-selection Protein Fat Carbohydrate Naloxone Caloric intake Endorphins 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Beaumont A, Hughes J (1979) Biology of opioid peptides. Annu Rev Pharmacol Toxicol 19:245–267Google Scholar
  2. Blundell JE, Latham CJ (1980) Characterisation of adjustments to the structure of feeding behavior following pharmacological treatment: Effects of amphetamine and fenfluramine and the antagonism produced by pimozide and methergoline. Pharmacol Biochem Behav 12:717–722Google Scholar
  3. Brands B, Thornhill JA, Hirst M, Gowdey CW (1979) Suppression of food intake and body weight gain by naloxone in rats. Life Sci 24:1773–1778Google Scholar
  4. Brown DR, Holtzman SG (1979) Suppression of deprivation-induced food and water intake in rats and mice by naloxone. Pharmac Biochem Behav 11:567–573Google Scholar
  5. Cooper SJ (1980) Naloxone: Effects on food and water consumption in the nondeprived and deprived rat. Psychopharmacology 71:1–6Google Scholar
  6. Frenk M, Rogers, GH (1979) The suppressant effects of naloxone on food and water intake in the rat. Behav Neural Biol 26:23–40Google Scholar
  7. Grandison L, Guidotti A (1977) Stimulation of food intake by muscimol and beta-endorphin. Neuropharmacology 16:533–536Google Scholar
  8. Guillemin R (1980) β-Lipotropin and endorphins: Implications of current knowledge. In: Krieger DT, Hughes JC (eds) Neuroendocrinology. Sinauer Associates, Sunderland, p 67Google Scholar
  9. Hetherington AW, Ranson SW (1942) The relation of various hypothalamic lesions to adiposity in the rat. J Comp Neurol 76:475–499Google Scholar
  10. Holtzman SG (1974) Behavioral effects of separate and combined administration of naloxone and d-amphetamine. J Pharmacol Exp Ther 189:51–60Google Scholar
  11. Holtzman SG (1979) Suppression of appetitive behavior in the rat by naloxone: Lack of effect of prior morphine dependence. Life Sci 24:219–226Google Scholar
  12. Kanarek RB, Feldman PF, Hanes C (1981a) Patterns of dietary selfselection in VMH-lesioned rats. Physiol Behav (in press)Google Scholar
  13. Kanarek RB, Ho L, Meade RG (1981b) Sustained decrease in fat consumption produced by amphetamine in rats maintained on a dietary self-selection regime. Pharmacol Biochem Behav 14:539–542Google Scholar
  14. King BM, Castellanos FX, Kastin AJ, Berzas MC, Mauk MD, Olson GA, Olson RD (1979) Naloxone-induced suppression of food intake in normal and hypothalamic obese rats. Pharmacol Biochem Behav 11:729–732Google Scholar
  15. Kuhar MJ, Pert CB, Snyder SH (1973) Regional distribution of opiate receptor binding in monkey and human brain. Nature 245:447–450Google Scholar
  16. Margules DL, Moisset B, Lewis MJ, Shibuya H, Pert CB (1978) β-Endorphin is associated with overeating in genetically obese mice (ob/ob) and rats (fa/fa). Science 202:988–991Google Scholar
  17. Marks-Kaufman R, Kanarek RB (1980) Morphine selectively influences macronutrient intake in the rat. Pharmacol Biochem Behav 12:427–430Google Scholar
  18. Morley JE (1980) The neuroendocrine control of appetite: the role of the endogenous opiates, cholecystokinin, TRH, gamma-amino-butyric acid and the diazepam receptor. Life Sci 27:355–368Google Scholar
  19. Orthen-Gambill N, Kanarek RB (1981) Differential effects of amphetamine and fenfluramine on dietary self-selection in rats. Pharmacol Biochem Behav (in press)Google Scholar
  20. Powley TL (1977) The ventromedial hypothalamic syndrome, satiety and a cephalic phase hypothesis. Psychol Rev 84:89–126Google Scholar
  21. Rogers GH, Frenk H, Taylor AN, Liebeskind JC (1978) Naloxone suppression of food and water intake in deprived rats. Proc West Pharmacol Soc 21:457–460Google Scholar
  22. Sanger DJ, McCarthy PS (1980) Differential effects of morphine on food and water intake in food deprived and freely feeding rats. Psychopharmacology 72:103–106Google Scholar
  23. Wikler A (1980) Opioid dependence. Mechanisms and treatment. Plenum Press, New YorkGoogle Scholar
  24. Wei E, Loh EH, Way EL (1973) Quantitative aspects of precipitated abstinence in morphine-dependent rats. J Pharmacol Exp Ther 184:398–403Google Scholar

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Robin Marks-Kaufman
    • 1
  • Robin B. Kanarek
    • 1
  1. 1.Department of PsychologyTufts UniversityMedfordUSA

Personalised recommendations