title: Actigraphy-based sleep parameters during the reinstatement of methamphetamine self-administration in rhesus monkeys.
abstract: The objective of this study was to investigate nighttime activity of nonhuman primates during extinction and cue- and drug-primed reinstatement of methamphetamine self-administration. Adult rhesus monkeys (Macaca mulatta; n = 5) self-administered methamphetamine (0.01 mg/kg/injection, i.v.) under a fixed-ratio 20 schedule of reinforcement. Saline infusions were then substituted for methamphetamine and stimulus light (drug-conditioned stimulus presented during drug self-administration) withheld until subjects reached extinction criteria. Drug- and cue-induced reinstatement effects were evaluated after i.v. noncontingent priming injections of methamphetamine (0.03, 0.1, or 0.3 mg/kg). Activity-based sleep measures were evaluated with Actiwatch monitors a week before (baseline nighttime activity parameters) and throughout the protocol. Although methamphetamine self-administration did not significantly affect nighttime activity compared to baseline, sleeplike parameters were improved during extinction compared to self-administration maintenance. Priming injection of 0.1 mg/kg methamphetamine, but not 0.03 or 0.3 mg/kg, induced significant reinstatement effects. These behavioral responses were accompanied by nighttime outcomes, with increased sleep fragmentation and decreased sleep efficiency in the night following 0.1 mg/kg methamphetamine-induced reinstatement. In the absence of both drug and drug-paired cues (extinction conditions), nighttime activity decreased compared to self-administration maintenance. Additionally, effective reinstatement conditions impaired sleeplike measures. Our data indicate that the reintroduction of the stimulus light as a drug-paired cue increased nighttime activity.
authors.affiliation: Yerkes National Primate Research Center, Emory University.
authors.forename: Laís F
authors.initials: LF
authors.lastname: Berro
authors.affiliation: Yerkes National Primate Research Center, Emory University.
authors.forename: Monica L
authors.initials: ML
authors.lastname: Andersen
authors.affiliation: Department of Psychobiology, Universidade Federal de São Paulo.
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.affiliation: Yerkes National Primate Research Center, Emory University.
authors.forename: Leonard L
authors.initials: LL
authors.lastname: Howell
mesh_terms: D056044:Actigraphy; D000818:Animals; D003216:Conditioning, Operant; D003463:Cues; D004305:Dose-Response Relationship, Drug; D005108:Extinction, Psychological; D005260:Female; D008253:Macaca mulatta; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage* / Q000494:pharmacology*; D012055:Reinforcement Schedule; D012646:Self Administration; D012890:Sleep / Q000187:drug effects* / Q000502:physiology*; D013997:Time Factors
chemical_list: D008694:Methamphetamine