Memory of conditioned taste aversion is erased by inhibition of PI3K in the insular cortex

Ilana Slouzkey, Kobi Rosenblum, Mouna Maroun

Research output: Contribution to journalArticlepeer-review

Abstract

The conditioned taste aversion (CTA) paradigm, in which association between a novel taste and visceral malaise is formed, gives a unique experimental setting to examine the mechanisms underlying memory acquisition and extinction processes. AKT is a main kinase of the phosphoinositide 3-kinase cascade (PI3K) and has been implicated in long-term memory. We have recently reported that blockade of PI3K in the basolateral amygdala (BLA) before retrieval of fear memory was associated with long-term reduction in fear responses, suggesting a possible role of PI3K inhibition in fear erasure. In this study, we aimed to elucidate whether PI3K has a similar role in the insular cortex (IC), which has a crucial role in CTA acquisition, consolidation, maintenance, and extinction. To that end, we (1) monitored AKT phosphorylation in the IC following CTA acquisition and extinction and (2) inhibited PI3K by local microinjection of the PI3K inhibitor LY294002 at different stages of CTA acquisition and extinction. Our results show that while AKT phosphorylation is increased following CTA learning, it is decreased following CTA extinction. Inhibition of AKT phosphorylation in the IC before or after the first CTA retrieval test resulted in reduction in the aversion index. This reduction in aversion is due to the erasure of the original CTA trace memory, as re-application of the unconditioned stimulus (lithium chloride) did not induce the recovery of aversion in LY294002-treated animals. Our present data add new evidence to suggest that PI3K is engaged in consolidation of aversive memories, as its inhibition is associated with erasure of CTA memory.

Original languageEnglish
Pages (from-to)1143-1153
Number of pages11
JournalNeuropsychopharmacology
Volume38
Issue number7
DOIs
StatePublished - Jun 2013

Bibliographical note

Funding Information:
This work was supported by Israel Science Foundation grant to MM. The authors thank Drs Guillaume Ferreira and Shunit Gal Ben-Ari for valuable comments.

Keywords

  • PI3K
  • conditioned taste aversion
  • consolidation
  • erasure
  • extinction
  • insular cortex

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Pharmacology

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