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Cav3.2 T-type calcium channel-dependent gene expression after retrieval of context-associated memory (right hippocampus)

ABSTRACT: Among all voltage-gated calcium channels, the T-type Ca2+ channels encoded by the Cav3 genes are highly expressed in the hippocampus, which is associated with contextual, temporal and spatial learning and memory. However, the specific involvement of the Cav3.2 T-type Ca2+ channel in these hippocampus-dependent types of learning and memory remains unclear. To investigate the functional role of the 1H channel in learning and memory, we subjected Cav3.2 homozygous, heterozygous knockout and their wild-type littermates to hippocampus-dependent behavioral tasks, including trace fear conditioning (TFC), the Morris water-maze and passive avoidance. The Cav3.2-/- mice performed normally in the Morris water-maze and auditory trace fear conditioning tasks but were impaired in the context-cued trace fear conditioning, step-down and step-through passive avoidance tasks. Furthermore, long-term potentiation (LTP) could be induced for 180 minutes in hippocampal slices of WTs and Cav3.2+/- mice, whereas LTP persisted for only 120 minutes in Cav3.2-/- mice. To determine whether the hippocampal formation is responsible for the impaired behavioral phenotypes , we next performed experiments locally knock down function of the Cav3.2 T-type Ca2+ channel in the hippocampus. Wild-type mice infused with mibefradil exhibited similar behaviors as homozygous knockouts. Finally, microarray analyses indicated that Cav3.2-/- and WT mice presented distinct hippocampal transcriptome profiles. Taken together, our results demonstrate that retrieval of context-associated memory is dependent on the Cav3.2 T-type Ca2+ channel.

ORGANISM(S): Mus musculus

PROVIDER: GSE30845 | GEO | 2013/02/28

SECONDARY ACCESSION(S): PRJNA154557

REPOSITORIES: GEO

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Project description:The mechanisms underlying age-associated memory impairment are not well understood. We have shown that the onset of memory disturbances in the aging brain is associated with altered hippocampal chromatin plasticity. During learning, aged mice display a specific deregulation of histone H4 lysine 12 (H4K12) acetylation. To analyze if deregulated H4K12 acetylation impacts on learning-induced gene-expression required for memory consolidation we performed a high-density oligonucleotide microarray to compare the entire hippocampal gene-expression profile of 3 and 16-month-old mice during memory consolidation. In order to identify genes differentially regulated between 3- and 16-month old mice upon fear conditioning we subjected 3- and 16-month old mice to fear conditioning (4 mice each group, total 8 mice) . Mice of the same age that were handled but not subjected to any of the employed behavior paradigms served as control (4 mice 3-month old and 4 mice 16-month old, total 8 mice). During fear conditioning mice are subjected to a novel context followed by a mild electric foot-shock (context-shock exposure). In order to identify genes that are differentially regulated upon fear conditioning and are specific to associative learning we also tested the hippocampal gene-expression profile of 3-month old mice subjected to the same context-exposure that is not followed by a foot-shock (Context-exposure) (4 mice) or receive an immediate foot shock once they are placed in the context and only afterwards are allowed to explore the context (shock-context exposure) (4 mice). In order to identify genes that are regulated upon fear conditioning and are specific to associative learning we compared the hippocampal gene-expression profile of mice subjected to fear conditioning (context-shock), context or shock-context exposure regarding to their age-matched control mice (3 month old) mentioned above (control). Hippocampi from each mice were tested resulting to 24 samples which were separately hybridized (OneColor Array Design).

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Cav3.2 T-type calcium channel-dependent gene expression after retrieval of context-associated memory (right hippocampus)

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