title: Agmatine blocks acquisition and re-acquisition of intravenous morphine self-administration in rats.
abstract: Our previous studies showed that agmatine inhibits morphine-induced conditioned place preference, locomotor sensitization and drug discrimination in rats. In the present study, we investigated the effects of agmatine on intravenous morphine self-administration in rats. At a dose of 80 mg/kg/infusion, agmatine did not substitute for intravenous morphine (0.5 mg/kg/infusion) self-administration, suggesting that agmatine itself has no reinforcing effect. However, pretreatment with agmatine (40 or 80 mg/kg, i.g.) significantly inhibited the acquisition of intravenous morphine self-administration as assessed by the nose-poke response and morphine intake. The mean number of days required to meet the acquisition criteria for intravenous morphine self-administration was significantly prolonged. After acquisition of intravenous morphine self-administration, chronic administration of agmatine (40 or 80 mg/kg x 30 days, bid, i.g.) during the extinction period significantly prevented the re-acquisition of intravenous morphine self-administration. The ability of agmatine to inhibit the acquisition and re-acquisition of intravenous morphine self-administration suggests a possible use of agmatine in the treatment of opioid dependence.
authors.affiliation: Beijing Institute of Pharmacology and Toxicology, TaiPing Road 27, Beijing 100850, China.
authors.forename: Rui-Bin
authors.initials: RB
authors.lastname: Su
authors.forename: Wei-Ping
authors.initials: WP
authors.lastname: Wang
authors.forename: Xin-Qiang
authors.initials: XQ
authors.lastname: Lu
authors.forename: Ning
authors.initials: N
authors.lastname: Wu
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Liu
authors.forename: Jin
authors.initials: J
authors.lastname: Li