The Journal of Neuroscience, November 8, 2006, 26(45):11582-11587; doi:10.1523/JNEUROSCI.2049-06.2006
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Behavioral/Systems/Cognitive
Blocking Memory Reconsolidation Reverses Memory-Associated Changes in Glutamate Receptor Expression
Jacqueline K. Rose and
Catharine H. Rankin
Department of Psychology and Brain Research Centre, University of British Columbia, Vancouver, British Columbia, Canada V6T 2B5
Correspondence should be addressed to Dr. Catharine Rankin, Brain Research Centre, 2211 Wesbrook Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 2B5. Email: crankin{at}psych.ubc.ca
It has been reported that consolidated memories can return to a labile state when reactivated and undergo a process of re-storage, termed reconsolidation, required for later recall. We investigated memory for a nonassociative learning task (habituation) and found that memory for this task also undergoes reconsolidation after recall. To investigate reconsolidation, we first demonstrated that adult Caenorhabditis elegans are capable of reliable memory 48 h after habituation training (p < 0.05). When heat shock was administered immediately after a reminder, response magnitudes of trained animals matched response levels of untrained animals: the inhibitory effects of heat shock on protein synthesis disrupted memory reconsolidation. Pharmacological blockade of non-NMDA-type glutamate receptors during reminder also eliminated 48 h retention. When expression levels of a specific glutamate receptor subunit (GLR-1) (40% homology to mammalian AMPA-type glutamate receptors) (Hart et al., 1995; Maricq et al., 1995) were measured 48 h after training, there was a significant decrease in trained compared with untrained controls. If trained worms were given a reminder followed immediately by heat shock, the effect of training on GLR-1 levels was reversed. From these studies, we conclude that both the behavioral expression of long-term memory for habituation and a cellular correlate of that memory (the alteration in expression levels of GLR-1) in C. elegans can be altered after retrieval. Furthermore, conditions that impair memory consolidation similarly disrupt memory reconsolidation, suggesting that similar mechanisms are involved.
Key words: habituation; reconsolidation; memory; glutamate receptors; C. elegans; retrieval-dependent amnesia
Received May 12, 2006;
revised Sept. 28, 2006;
accepted Sept. 29, 2006.
Correspondence should be addressed to Dr. Catharine Rankin, Brain Research Centre, 2211 Wesbrook Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 2B5. Email: crankin{at}psych.ubc.ca