Reactivating fear memory under propranolol resets pre-trauma levels of dendritic spines in basolateral amygdala but not dorsal hippocampus neurons

Gisella Vetere, Valentina Piserchia, Antonella Borreca, Giovanni Novembre, Massimiliano Aceti, Martine Ammassari-Teule

Research output: Contribution to journalArticle

Abstract

Fear memory enhances connectivity in cortical and limbic circuits but whether treatments disrupting fear reset connectivity to pre-trauma level is unknown. Here we report that C56BL/6J mice exposed to a tone-shock association in context A (conditioning), and briefly re-exposed to the same tone-shock association in context B (reactivation), exhibit strong freezing to the tone alone delivered 48 h later in context B (long term fear memory). This intense fear response is associated with a massive increase in dendritic spines and phospho-Erk (p-ERK) signaling in basolateral amygdala (BLA) but neurons. We then show that propranolol (a central/peripheral β-adrenergic receptor blocker) administered before, but not after, the reactivation trial attenuates long term fear memory assessed drug free 48 h later, and completely prevents the increase in spines and p-ERK signaling in BLA neurons. An increase in spines, but not of p-ERK, was also detected in the dorsal hippocampus (DH) of the conditioned mice. DH spines, however, were unaffected by propranolol suggesting their independence from the ERK/β-ARs cascade. We conclude that propranolol selectively blocks dendritic spines and p-ERK signaling enhancement in the BLA; its effect on fear memory is, however, less pronounced suggesting that the persistence of spines at other brain sites decreases the sensitivity of the fear memory trace to treatments selectively targeting βARs in the BLA.

Original languageEnglish
Article number211
JournalFrontiers in Behavioral Neuroscience
Volume7
Issue numberDEC
DOIs
Publication statusPublished - Dec 23 2013

Keywords

  • Amygdala
  • Dendritic spines
  • Fear memory reactivation
  • Hippocampus
  • p-ERK
  • Propranolol

ASJC Scopus subject areas

  • Behavioral Neuroscience
  • Cognitive Neuroscience
  • Neuropsychology and Physiological Psychology

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