 |
||||
|
||||
|
||||
|
||||
Previous Article | Next Article
The Journal of Neuroscience, February 1, 2003, 23(3):737
BRIEF COMMUNICATION
Inhibition of mRNA and Protein Synthesis in the CA1 Region of the Dorsal Hippocampus Blocks Reinstallment of an Extinguished Conditioned Fear ResponseMartín Cammarota1, 2, Lia R. M. Bevilaqua1, Daniel Kerr1, Jorge H. Medina2, and Iván Izquierdo1 1 Memorial Center, Department of Biochemistry, Instituto de Ciências Biológicas e da Saúde, Federal University of Río Grande do Sul, Porto Alegre 90035-003, RS, Brazil, and 2 Neuroreceptor Laboratory, Institute of Cellular Biology and Neurosciences, Faculty of Medicine, University of Buenos Aires, Buenos Aires 1121, Argentina
Memories are extinguished by the repeated presentation of a conditioned stimulus in the absence of an unconditioned stimulus to which it has been associated. It is believed that extinction establishes a new hierarchy of responses rather than an actual forgetting of the original response, which can usually reappear spontaneously after interruption of the extinction process. In this study, our aim was to analyze how profound extinction can be. Rats were trained in a one-trial, step-down inhibitory avoidance paradigm and then were exposed to several extinction sessions in which they were allowed to freely explore the apparatus for 30 sec after having stepped down. Extinction was complete enough so that there was no spontaneous recovery, and test session performance could not be enhanced by pharmacological agents with well known facilitative actions on retrieval. After being submitted to a new training session, control animals reacquired the avoidance response; however, animals failed to do so after receiving bilateral intra-CA1 infusions of either the protein synthesis inhibitor anisomycin or the mRNA synthesis blocker 5,6-dichloro-1-
-d-ribofuranosyl benzimidazole 15 min before the retraining session. Our results indicate that extinction can be carried to a point at which reinstallment of the conditioned response requires, like the original learning, de novo gene expression and protein synthesis in the CA1 region of the dorsal hippocampus.
Key words: memory; learning; extinction; reinstallment, hippocampus; protein synthesis; gene expression
Copyright © 2003 Society for Neuroscience 0270-6474/03/233737-05$05.00/0
This article has been cited by other articles:
D. Moncada and H. Viola
Induction of Long-Term Memory by Exposure to Novelty Requires Protein Synthesis: Evidence for a Behavioral Tagging
J. Neurosci., July 11, 2007; 27(28): 7476 - 7481.
[Abstract] [Full Text] [PDF]
T. W. Bredy, H. Wu, C. Crego, J. Zellhoefer, Y. E. Sun, and M. Barad
Histone modifications around individual BDNF gene promoters in prefrontal cortex are associated with extinction of conditioned fear
Learn. Mem., April 6, 2007; 14(4): 268 - 276.
[Abstract] [Full Text] [PDF]
J. I. Rossato, L. R.M. Bevilaqua, J. C. Myskiw, J. H. Medina, I. Izquierdo, and M. Cammarota
On the role of hippocampal protein synthesis in the consolidation and reconsolidation of object recognition memory
Learn. Mem., January 1, 2007; 14(1-2): 36 - 46.
[Abstract] [Full Text] [PDF]
J. I. Rossato, L. R.M. Bevilaqua, J. H. Medina, I. Izquierdo, and M. Cammarota
Retrieval induces hippocampal-dependent reconsolidation of spatial memory
Learn. Mem., July 1, 2006; 13(4): 431 - 440.
[Abstract] [Full Text] [PDF]
M. Cammarota, L. R.M. Bevilaqua, J. H. Medina, and I. Izquierdo
Retrieval Does Not Induce Reconsolidation of Inhibitory Avoidance Memory
Learn. Mem., September 1, 2004; 11(5): 572 - 578.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|