title: Chronic methamphetamine treatment induces oxytocin receptor up-regulation in the amygdala and hypothalamus via an adenosine A2A receptor-independent mechanism.
abstract: There is mounting evidence that the neuropeptide oxytocin is a possible candidate for the treatment of drug addiction. Oxytocin was shown to reduce methamphetamine self-administration, conditioned place-preference, hyperactivity and reinstatement in rodents, highlighting its potential for the management of methamphetamine addiction. Thus, we hypothesised that the central endogenous oxytocinergic system is dysregulated following chronic methamphetamine administration. We tested this hypothesis by examining the effect of chronic methamphetamine administration on oxytocin receptor density in mice brains with the use of quantitative receptor autoradiographic binding. Saline (4ml/kg/day, i.p.) or methamphetamine (1mg/kg/day, i.p.) was administered daily for 10 days to male, CD1 mice. Quantitative autoradiographic mapping of oxytocin receptors was carried out with the use of [(125)I]-vasotocin in brain sections of these animals. Chronic methamphetamine administration induced a region specific upregulation of oxytocin receptor density in the amygdala and hypothalamus, but not in the nucleus accumbens and caudate putamen. As there is evidence suggesting an involvement of central adenosine A2A receptors on central endogenous oxytocinergic function, we investigated whether these methamphetamine-induced oxytocinergic neuroadaptations are mediated via an A2A receptor-dependent mechanism. To test this hypothesis, autoradiographic oxytocin receptor binding was carried out in brain sections of male CD1 mice lacking A2A receptors which were chronically treated with methamphetamine (1mg/kg/day, i.p. for 10 days) or saline. Similar to wild-type animals, chronic methamphetamine administration induced a region-specific upregulation of oxytocin receptor binding in the amygdala and hypothalamus of A2A receptor knockout mice and no genotype effect was observed. These results indicate that chronic methamphetamine use can induce profound neuroadaptations of the oxytocinergic receptor system in brain regions associated with stress, emotionality and social bonding and that these neuroadaptations are independent on the presence of A2A receptors. These results may at least partly explain some of the behavioural consequences of chronic methamphetamine use.
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK.
authors.forename: Panos
authors.initials: P
authors.lastname: Zanos
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK.
authors.forename: Sherie R
authors.initials: SR
authors.lastname: Wright
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK.
authors.forename: Polymnia
authors.initials: P
authors.lastname: Georgiou
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK.
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Yoo
authors.affiliation: Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, B-1070, Belgium.
authors.forename: Catherine
authors.initials: C
authors.lastname: Ledent
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK.
authors.forename: Susanna M
authors.initials: SM
authors.lastname: Hourani
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Kitchen
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK.
authors.forename: Raphaelle
authors.initials: R
authors.lastname: Winsky-Sommerer
authors.affiliation: Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK. Electronic address: a.bailey@surrey.ac.uk.
authors.forename: Alexis
authors.initials: A
authors.lastname: Bailey
mesh_terms: D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D005260:Female; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D018045:Receptors, Oxytocin / Q000187:drug effects* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D043705:Receptor, Adenosine A2A; D018045:Receptors, Oxytocin; D008694:Methamphetamine
keywords: A(2A) receptor; Amygdala; Hypothalamus; Methamphetamine; Oxytocin