RESEARCH REPORTSNormal extinction and reinstatement of morphine-induced conditioned place preference in the GluA1-KO mouse lineKiiskinen, Tuomo; Korpi, Esa R.; Aitta-aho, TeemuAuthor Information Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland Correspondence to Teemu Aitta-aho, PhD, Department of Pharmacology, Faculty of Medicine P.O. Box 63, University of Helsinki, FI-00014 Helsinki, Finland E-mail: [email protected] Behavioural Pharmacology: August 2019 - Volume 30 - Issue 5 - p 405-411 doi: 10.1097/FBP.0000000000000449 Buy Metrics Abstract Extinction and reinstatement of morphine-induced conditioned place preference were studied in glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-receptor GluA1 subunit-deficient mice (global GluA1-KO mice). In line with previous findings, both acquisition and expression of conditioned place preference to morphine (20 mg/kg, subcutaneously) were fully functional in GluA1 KO mice compared with wild-type littermate controls (GluA1-WT), thus enabling the study of extinction. With a 10-session extinction paradigm, the GluA1 KO mice showed complete extinction similar to that of the GluA1-WT mice. Morphine-induced reinstatement (10 mg/kg, subcutaneously) was detected in both mouse lines. GluA1 KO mice moved more during all the phases of the experiment, including the place conditioning trials, extinction sessions, and place preference tests. The results suggest that the GluA1 subunit may be dispensable or prone to compensation at the neural circuitries delineating extinction and reinstatement. The GluA1 KO mice show altered long-term between-session habituation, which extends longer than previously anticipated. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.