title: Naloxone treatment alters gene expression in the mesolimbic reward system in 'junk food' exposed offspring in a sex-specific manner but does not affect food preferences in adulthood.
abstract: We have previously reported that the opioid receptor blocker, naloxone, is less effective in reducing palatable food intake in offspring exposed to a maternal cafeteria diet during the perinatal period, implicating a desensitization of the central opioid pathway in the programming of food preferences. The present study aimed to investigate the effect of a maternal cafeteria diet and naloxone treatment on the development of the mesolimbic reward pathway and food choices in adulthood. We measured mRNA expression of key components of the reward pathway (mu-opioid receptor, proenkephalin, tyrosine hydroxylase, D1 and D2 receptors and the dopamine active transporter (DAT)) in the nucleus accumbens (NAc) and ventral tegmental area (VTA) of the offspring of control and cafeteria fed (JF) dams at weaning and after a 10-day naloxone treatment post-weaning and determined food preferences in adulthood in the remaining offspring. Naloxone treatment decreased the expression of DAT by 8.2 fold in female control offspring but increased it by 4.3 fold in female offspring of JF dams relative to the saline-injected reference groups. Proenkephalin mRNA expression was higher in the NAc of female JF offspring compared to controls, independent of naloxone treatment (P<0.05). There was no effect of naloxone treatment on food preferences in adulthood in either control or JF offspring. These data indicate that prenatal exposure to a cafeteria diet alters the impact of opioid signaling blockade in the early post-weaning period on gene expression in the central reward pathway in a sex specific manner, but that these changes in gene expression do not appear to have any persistent impact on food preferences in adulthood.
authors.affiliation: FOODplus Research Centre, School of Agriculture Food and Wine, The University of Adelaide, Adelaide 5064, Australia.
authors.forename: J R
authors.initials: JR
authors.lastname: Gugusheff
authors.affiliation: FOODplus Research Centre, School of Agriculture Food and Wine, The University of Adelaide, Adelaide 5064, Australia; Sansom Institute for Health Research, School of Pharmacy and Medical Science, University of South Australia, Adelaide 5001, Australia.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Ong
authors.affiliation: FOODplus Research Centre, School of Agriculture Food and Wine, The University of Adelaide, Adelaide 5064, Australia; Sansom Institute for Health Research, School of Pharmacy and Medical Science, University of South Australia, Adelaide 5001, Australia. Electronic address: beverly.muhlhausler@adelaide.edu.au.
authors.forename: B S
authors.initials: BS
authors.lastname: Muhlhausler
mesh_terms: D000818:Animals; D059305:Diet, High-Fat / Q000009:adverse effects; D019422:Dietary Sucrose / Q000009:adverse effects; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D004435:Eating / Q000187:drug effects; D004745:Enkephalins / Q000235:genetics / Q000378:metabolism; D005247:Feeding Behavior; D005260:Female; D005518:Food Preferences / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000235:genetics / Q000378:metabolism; D012201:Reward; D012727:Sex Characteristics; D017557:Ventral Tegmental Area / Q000187:drug effects*
chemical_list: D019422:Dietary Sucrose; D050483:Dopamine Plasma Membrane Transport Proteins; D004745:Enkephalins; D009292:Narcotic Antagonists; D011498:Protein Precursors; D012333:RNA, Messenger; D011954:Receptors, Dopamine; C029992:proenkephalin; D009270:Naloxone
keywords: High-fat diet; Opioids; Programming