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Learning modulation by endogenous hippocampal IL‐1: Blockade of endogenous IL‐1 facilitates memory formation
Author(s) -
Depino Amaicha M.,
Alonso Mariana,
Ferrari Carina,
del Rey Adriana,
Anthony Daniel,
Besedovsky Hugo,
Medina Jorge H.,
Pitossi Fernando
Publication year - 2003
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.10164
Subject(s) - hippocampal formation , memory consolidation , neuroscience , psychology , endogeny , hippocampus , habituation , inhibitory postsynaptic potential , receptor antagonist , receptor , antagonist , biology , medicine , endocrinology
The interleukin‐1 (IL‐1) cytokine family (IL‐1α, IL‐β, and the IL‐1 receptor antagonist) is involved in immune and inflammatory responses both in the brain and in the periphery. Recently, it has also been shown to influence behavior and memory consolidation. However, within the experimental systems studied, it has remained unclear whether the role of IL‐1β is associated solely with a pathophysiological process or whether it is a neuromodulator in normal adult brain. To evaluate the involvement of the nonpathological endogenous IL‐1 system in learning, we studied the expression of IL‐1α, IL‐1β, and IL‐1ra during memory consolidation. We observed a learning‐specific hippocampal IL‐1α mRNA induction, but not that of IL‐1β or IL‐1ra mRNAs, after inhibitory avoidance training. Moreover, when IL‐1 receptor activity was inhibited using an adenoviral vector that expresses the IL‐1 receptor antagonist (IL‐1ra) in the hippocampus, both short‐term and long‐term memory retention scores were facilitated. In contrast, endogenous hippocampal IL‐1 played no role in the habituation to a novel environment. These results demonstrate that endogenous hippocampal IL‐1 specifically modulates a fear‐motivated learning task, and suggest that IL‐1α activity in the CNS is part of the hippocampal memory processing. © 2003 Wiley‐Liss, Inc.