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Individual phases of contextual fear conditioning differentially modulate dorsal and ventral hippocampal GluA1‐3, GluN1‐containing receptor complexes and subunits
Author(s) -
Sase Sunetra,
Sase Ajinkya,
Sialana Fernando J.,
Gröger Marion,
Bennett Keiryn L.,
Stork Oliver,
Lubec Gert,
Li Lin
Publication year - 2015
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.22470
Subject(s) - protein subunit , hippocampal formation , hippocampus , chemistry , memory consolidation , immunohistochemistry , ampa receptor , receptor , neuroscience , dorsum , psychology , biology , glutamate receptor , anatomy , biochemistry , immunology , gene
In contextual fear conditioning (CFC), the use of pharmacological and lesion approaches has helped to understand that there are differential roles for the dorsal hippocampus (DH) and the ventral hippocampus (VH) in the acquisition, consolidation and retrieval phases. Concomitant analysis of the DH and the VH in individual phases with respect to α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionate receptors and N‐methyl‐ d ‐aspartate receptor subtype N1 (GluN1) ‐containing complexes (RCC) and subunits has not been reported so far. Herein, CFC was performed in mice that were euthanized at different time points. DH and VH samples were taken for the determination of RCC and subunit levels using BN‐ and SDS‐PAGE, respectively, with subsequent Western blotting. Evaluation of spine densities, morphology, and immunohistochemistry of GluA1 and GluA2 was performed. In the acquisition phase levels of GluA1‐RCC and subunits in VH were increased. In the consolidation phase GluA1‐ and GluA2‐RCC levels were increased in DH and VH, while both receptor subunit levels were increased in the VH only. In the retrieval phase GluA1‐RCC, subunits thereof and GluA2‐RCC were increased in DH and VH, whereas GluA2 subunits were increased in the VH only. GluN1‐RCC levels were increased in acquisition and consolidation phase, while subunit levels in the acquisition phase were increased only in the DH. The immunohistochemical studies in the individual phases in subareas of hippocampus supported immunochemical changes of GluA1 and GluA2 RCC's. Dendritic spine densities and the prevalence of thin spines in the acquisition phase of VH and mushroom spines in the retrieval phase of the VH and DH were increased. The findings from the current study suggest different receptor and receptor complex patterns in the individual phases in CFC and in DH and VH. The results propose that different RCCs are formed in the individual phases and that VH and DH may be involved in CFC. © 2015 Wiley Periodicals, Inc.