Opioid modulation of sucrose intake in CD-1 mice: effects of gender and housing conditions.
The effects of naltrexone (1 mg/kg, sc.) on consumption of a 5% sucrose solution were observed in nondeprived adult female CD-1 mice and in male mice. Males were either individually housed or were housed in pairs. Naltrexone significantly reduced the consumption of the sucrose in both female and male mice; in the case of the males the administration of naltrexone produced an intake pattern identical to that obtained for a less palatable (1.5%) sucrose solution in control conditions. There was no difference between subordinate and dominant males, neither in sucrose intake nor in the response to the naltrexone treatment. In a second experiment, it was shown that switching from a 5% to a 10% solution was sufficient to overcome naltrexone's suppressant effect in female mice, conversely this was not seen in the males. In general, the data are consistent with the view that opioid antagonists reduce effective palatability of sweet sucrose solutions in mice. There was no evidence that social isolation and stress related to subordination affected male mice's sucrose intake and response to the naltrexone challenge.
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Dipartimento di Biologia e Fisiologia Generali, Universita degli Studi di Parma, Italy.
Cooper
S J
SJ
D000818:Animals; D004291:Dominance-Subordination; D005260:Female; D005518:Food Preferences / Q000187:drug effects / Q000502:physiology*; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D009271:Naltrexone / Q000494:pharmacology; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology*; D012737:Sex Factors; D012931:Social Environment; D012934:Social Isolation; D013395:Sucrose / Q000008:administration & dosage; D013649:Taste / Q000187:drug effects / Q000502:physiology*
D011957:Receptors, Opioid; D013395:Sucrose; D009271:Naltrexone