title: A maternal "junk-food" diet reduces sensitivity to the opioid antagonist naloxone in offspring postweaning.
abstract: Perinatal exposure to a maternal "junk-food" diet has been demonstrated to increase the preference for palatable diets in adult offspring. We aimed to determine whether this increased preference could be attributed to changes in μ-opioid receptor expression within the mesolimbic reward pathway. We report here that mRNA expression of the μ-opioid receptor in the ventral tegmental area (VTA) at weaning was 1.4-fold (males) and 1.9-fold (females) lower in offspring of junk-food (JF)-fed rat dams than in offspring of dams fed a standard rodent diet (control) (P<0.05). Administration of the opioid antagonist naloxone to offspring given a palatable diet postweaning significantly reduced fat intake in control offspring (males: 7.7 ± 0.7 vs. 5.4 ± 0.6 g/kg/d; females: 6.9 ± 0.3 vs. 3.9 ± 0.5 g/kg/d; P<0.05), but not in male JF offspring (8.6 ± 0.6 vs. 7.1 ± 0.5 g/kg/d) and was less effective at reducing fat intake in JF females (42.2 ± 6.0 vs. 23.1 ± 4.1% reduction, P<0.05). Similar findings were observed for total energy intake. Naloxone treatment did not affect intake of standard rodent feed in control or JF offspring. These findings suggest that exposure to a maternal junk-food diet results in early desensitization of the opioid system which may explain the increased preference for junk food in these offspring.
authors.affiliation: FOODplus Research Centre, School of Agriculture Food and Wine, The University of Adelaide, Adelaide 5064, Australia.
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Gugusheff
authors.forename: Zhi Yi
authors.initials: ZY
authors.lastname: Ong
authors.forename: Beverly S
authors.initials: BS
authors.lastname: Muhlhausler
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004041:Dietary Fats / Q000009:adverse effects* / Q000494:pharmacology; D004435:Eating / Q000187:drug effects*; D005260:Female; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D009292:Narcotic Antagonists; D017450:Receptors, Opioid, mu; D009270:Naloxone