Post-session injections of a protein synthesis inhibitor, cycloheximide do not alter saccharin self-administration

A large body of evidence indicates that reactivation of aversive memories leads to protein synthesis-dependent memory reconsolidation which can be disrupted by cycloheximide (CHX) and other protein synthesis inhibitors. The aim of the present study was to investigate whether CHX would alter maintenance of well-trained instrumental responding for 0.1% saccharin. Male Wistar rats were trained to lever press for saccharin. When lever pressing stabilized, experimental self-administration sessions with CHX (3 mg/kg, s.c.) started. The animals received four experimental sessions, with each session separated by 5 days. The protein synthesis inhibitor was injected immediately after the experimental sessions 1-3. Repeated post-session injections of CHX did not alter saccharin self-administration. A two-bottle choice test conducted after the last experimental session revealed that CHX had not induced any conditioned taste aversion to 0.1% saccharin. The present results suggest that well-consolidated long-term memory of an appetitive instrumental task does not depend on de novo protein synthesis. (C) 2008 Elsevier Inc. All rights reserved.