title: The expression of amphetamine sensitization is dissociable from anxiety and aversive memory: Effect of an acute injection of amphetamine.
abstract: The repeated administration of amphetamine can lead to locomotor sensitization. Although the repeated administration of amphetamine has been associated with anxiety and impaired working memory, it is uncertain if expression of amphetamine sensitization is associated with modifications of emotional memories. To address this issue, rats were injected once daily with amphetamine for five consecutive days (1.5mg/kg). After four days of withdrawal, rats were delivered an acute amphetamine injection to assess the expression of sensitization. A single exposure to an elevated plus maze (EPM), 24h after the last injection of amphetamine, showed that amphetamine sensitization is not accompanied by anxiety. Next, aversive memory was assessed using an 11day inter-trial interval between the EPM Trial 1 and EPM Trial 2. Rats administered with saline showed a percentage of open arms time (% OAT) in Trial 2 that was comparable to Trial 1, demonstrating a reduction in the retrieval of aversive memory. However, rats sensitized after the EPM Trial 1 showed a significant decrease in the % OAT in Trial 2. Importantly, a decrease in the % OAT in Trial 2 compared to Trial 1 was also observed after a single injection of amphetamine 24h before Trial 2. These results show a facilitation in the retrieval of aversive memory, and suggest that a previous amphetamine injection is enough to produce a protracted activation of neural circuits necessary for the retrieval of aversive memory.
authors.affiliation: Departamento de Farmacia and Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Rafael Ignacio
authors.initials: RI
authors.lastname: Gatica
authors.affiliation: Departamento de Farmacia and Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Enzo
authors.initials: E
authors.lastname: Pérez-Valenzuela
authors.affiliation: Department of Anatomy & Neurobiology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico, 00936.
authors.forename: Demetrio
authors.initials: D
authors.lastname: Sierra-Mercado
authors.affiliation: Departamento de Farmacia and Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile, Santiago, Chile. Electronic address: jfuentea@uc.cl.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Fuentealba
mesh_terms: D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001007:Anxiety / Q000523:psychology*; D001362:Avoidance Learning / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D009043:Motor Activity / Q000187:drug effects*; D017207:Rats, Sprague-Dawley
chemical_list: D000697:Central Nervous System Stimulants; D000661:Amphetamine
keywords: Amphetamine; Anxiety; Aversive memory; Elevated plus maze; Locomotor sensitization