title: Brain Disposition ofcis-para-Methyl-4-Methylaminorex (cis-4,4'-DMAR) and Its Potential Metabolites after Acute and Chronic Treatment in Rats: Correlation with Central Behavioral Effects.
abstract: para-Methyl-4-methylaminorex (4,4'-DMAR) is a phenethylamine derivative with psychostimulant activity whose abuse has been associated with several deaths and a wide range of adverse effects. We recently validated a high-performance liquid chromatography-tandem mass spectrometry method to measure the compound's concentrations in plasma, and we applied it to describe the pharmacokinetic properties of 4,4'-DMAR after a single dose in rats. In this study, we investigated the brain disposition and metabolism ofcis-4,4'-DMAR after intraperitoneal injection as well as its central behavioral effects. Locomotor activity increased after a single injection of 10 mg/kg, peaking at 2 hours and disappearing at 5 hours; in these conditions, brain absorption was very rapid, (tmax= 30-60 minutes) and large (brain-to-plasma ratio = 24); the half-life was approximately 50 minutes. After 14 daily doses, the compound's effect on locomotor activity was greater (approximately 20% compared with the effect after the first dose), but not for pharmacokinetic reasons. Using high-resolution mass spectrometry, we also identified four metabolites ofcis-4,4'-DMAR in the plasma and brain of treated rats. Semiquantitative analysis indicated low brain permeability and very low brain concentrations, suggesting that these metabolites do not contribute to central behavioral effects; however, the metabolite originating from oxidation of thepara-methyl group (M2) persisted in the plasma longer and at higher concentrations than the parent molecule and could be used to evaluate drug intake in human consumers. Finally, we describe the rewarding effect ofcis-4,4'-DMAR in the conditioning place preference test, suggesting a high risk of addiction in humans.
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy jacopo.lucchetti@marionegri.it.
authors.forename: Jacopo
authors.initials: J
authors.lastname: Lucchetti
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Claudio M
authors.initials: CM
authors.lastname: Marzo
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Passoni
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Di Clemente
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Moro
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Bagnati
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Gobbi
authors.affiliation: Departments of Molecular Biochemistry and Pharmacology (J.L., M.G.), Neuroscience (C.M.M., A.D.C., F.M., L.C.), and Environmental Health Science (A.P., R.B.), IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Cervo
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004334:Drug Administration Schedule; D013287:Illicit Drugs / Q000378:metabolism* / Q000494:pharmacology*; D008124:Locomotion / Q000187:drug effects* / Q000502:physiology; D008297:Male; D010080:Oxazoles / Q000008:administration & dosage* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution / Q000187:drug effects / Q000502:physiology
chemical_list: D013287:Illicit Drugs; D010080:Oxazoles; C000598109:para-methyl-4-methylaminorex