Altered gene activity correlated with long-term memory formation of conditioned taste aversion in Lymnaea

Sachiyo Azami, Akiko Wagatsuma, Hisayo Sadamoto, Dai Hatakeyama, Takeshi Usami, Manabu Fujie, Ryo Koyanagi, Kaoru Azumi, Yutaka Fujito, Ken Lukowiak, Etsuro Ito*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


The pond snail Lymnaea stagnalis is capable of learning conditioned taste aversion (CTA) and then consolidating that learning into long-term memory (LTM) that persists for at least 1 month. LTM requires de novo protein synthesis and altered gene activity. Changes in gene activity in Lymnaea that are correlated with, much less causative, memory formation have not yet been identified. As a first step toward rectifying this situation, we constructed a cDNA microarray with mRNAs extracted from the central nervous system (CNS) of Lymnaea. We then, using this microarray assay, identified genes whose activity either increased or decreased following CTA memory consolidation. We also identified genes whose expression levels were altered after inhibition of the cyclic AMP response element-binding protein (CREB) that is hypothesized to be a key transcription factor for CTA memory. We found that the molluscan insulin-related peptide II (MIP II) was up-regulated during CTA-LTM, whereas the gene encoding pedal peptide preprohormone (Pep) was down-regulated by CREB2 RNA interference. We next examined mRNAs of MIP II and Pep using real-time RT-PCR with SYBR Green. The MIP II mRNA level in the CNS of snails exhibiting "good" memory for CTA was confirmed to be significantly higher than that from the CNS of snails exhibiting "poor" memory. In contrast, there was no significant difference in expression levels of the Pep mRNA between "good" and "poor" performers. These data suggest that in Lymnaea MIP II may play a role in the consolidation process that forms LTM following CTA training.

Original languageEnglish
Pages (from-to)1610-1620
Number of pages11
JournalJournal of Neuroscience Research
Issue number7
Publication statusPublished - 2006 Nov 15
Externally publishedYes


  • Conditioned taste aversion
  • Gene activity
  • Long-term memory
  • Lymnaea stagnalis

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience


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