title: Underlying mechanism of combined effect of methamphetamine and morphine on lethality in mice and therapeutic potential of cooling.
abstract: An increase in polydrug abuse is a major problem worldwide. A previous study showed that coadministration of methamphetamine and morphine induced lethality in rodents and humans. However, the underlying mechanisms by which the lethality is increased by the coadministration of methamphetamine and morphine have not been fully understood. Therefore, the present study was designed to determine the mechanism of increased lethality induced by methamphetamine and morphine. Coadministered methamphetamine and morphine increased the lethality by more than 70% in BALB/c mice. Pretreatment with NMDA-receptor antagonists, such as MK-801 and 3-((R)-2-carboxypiperazin-4-yl) propyl-1-phosphonic acid (CPP), and benzamide [poly(ADP-ribose) polymerase (PARP) inhibitor] significantly attenuated the increased lethality induced by methamphetamine and morphine. Furthermore, the lethal effect induced by methamphetamine and morphine was completely attenuated by immediate cooling after the coadministration of methamphetamine and morphine. It has been reported that methamphetamine-induced neurotoxicity can be blocked by lowering the temperature, and this effect might be mediated by a reduction of release of free radicals. These results suggest that activation of NMDA receptors and PARP play an important role in the increased lethality induced by methamphetamine and morphine.
authors.affiliation: Department of Emergency Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
authors.forename: Mizuho
authors.initials: M
authors.lastname: Namiki
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Mori
authors.forename: Toshiko
authors.initials: T
authors.lastname: Sawaguchi
authors.forename: Shinobu
authors.initials: S
authors.lastname: Ito
authors.forename: Tadashi
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001549:Benzamides / Q000008:administration & dosage / Q000494:pharmacology; D001831:Body Temperature / Q000187:drug effects; D016291:Dizocilpine Maleate / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D006321:Heart / Q000187:drug effects; D007036:Hypothermia, Induced; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage / Q000633:toxicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D009020:Morphine / Q000008:administration & dosage / Q000633:toxicity*; D009206:Myocardium / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D000071137:Poly (ADP-Ribose) Polymerase-1; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D019966:Substance-Related Disorders / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D015996:Survival Rate; D013997:Time Factors
chemical_list: D001549:Benzamides; D004338:Drug Combinations; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D016194:Receptors, N-Methyl-D-Aspartate; D008694:Methamphetamine; D016291:Dizocilpine Maleate; C037689:benzamide; D009020:Morphine; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases