title: Extracellular signal-regulated kinase activation is required for consolidation and reconsolidation of memory at an early stage of ontogenesis.
abstract: The ability to form long-term memories exists very early during ontogeny; however, the properties of early memory processes, brain structures involved and underlying cellular mechanisms are poorly defined. Here, we examine the role of extracellular signal-regulated kinase (ERK), a member of the mitogen-activated protein kinase/ERK signaling cascade, which is crucial for adult memory, in the consolidation and reconsolidation of an early memory using a conditioned taste aversion paradigm in 3-day-old rat pups. We show that intraperitoneal injection of SL327, the upstream mitogen-activated protein kinase kinase inhibitor, impairs both consolidation and reconsolidation of early memory, leaving short-term memory after acquisition and after reactivation intact. The amnesic effect of SL327 diminishes with increasing delays after acquisition and reactivation. Biochemical analyses revealed ERK hyperphosphorylation in the amygdala but not the hippocampus following acquisition, suggesting functional activation of the amygdala as early as post-natal day 3, although there was no clear evidence for amygdalar ERK activation after reactivation. These results indicate that, despite an immature brain, the basic properties of memory and at least some of the molecular mechanisms and brain structures implicated in aversion memory share a number of similarities with the adult and emerge very early during ontogeny.
authors.affiliation: Université Paris-Sud, UMR 8620, Université Paris-Sud, Orsay, France. solene.languille@u-psud.fr
authors.forename: Solène
authors.initials: S
authors.lastname: Languille
authors.forename: Sabrina
authors.initials: S
authors.lastname: Davis
authors.forename: Paulette
authors.initials: P
authors.lastname: Richer
authors.forename: Cristina
authors.initials: C
authors.lastname: Alcacer
authors.forename: Serge
authors.initials: S
authors.lastname: Laroche
authors.forename: Bernard
authors.initials: B
authors.lastname: Hars
mesh_terms: D000375:Aging; D000607:Aminoacetonitrile / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005260:Female; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013649:Taste / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; C424127:SL 327; D000607:Aminoacetonitrile; D048049:Extracellular Signal-Regulated MAP Kinases