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Object-place recognition learning triggers rapid induction of plasticity-related immediate early genes and synaptic proteins in the rat dentate gyrus.

Soulé J, Penke Z, Kanhema T, Alme MN, Laroche S, Bramham CR - Neural Plast. (2009)

Bottom Line: Here, we examined expression of the plasticity-associated immediate early genes (Arc, Zif268, and Narp) in the dentate gyrus following long-term object-place recognition learning in rats.RT-PCR analysis from dentate gyrus tissue collected shortly after training did not reveal learning-specific changes in Arc mRNA expression.Thus, object-place recognition triggers rapid, blade-specific upregulation of plasticity-associated immediate early genes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedicine and Bergen Mental Health Research Center, University of Bergen, Bergen, Norway.

ABSTRACT
Long-term recognition memory requires protein synthesis, but little is known about the coordinate regulation of specific genes. Here, we examined expression of the plasticity-associated immediate early genes (Arc, Zif268, and Narp) in the dentate gyrus following long-term object-place recognition learning in rats. RT-PCR analysis from dentate gyrus tissue collected shortly after training did not reveal learning-specific changes in Arc mRNA expression. In situ hybridization and immunohistochemistry were therefore used to assess possible sparse effects on gene expression. Learning about objects increased the density of granule cells expressing Arc, and to a lesser extent Narp, specifically in the dorsal blade of the dentate gyrus, while Zif268 expression was elevated across both blades. Thus, object-place recognition triggers rapid, blade-specific upregulation of plasticity-associated immediate early genes. Furthermore, Western blot analysis of dentate gyrus homogenates demonstrated concomitant upregulation of three postsynaptic density proteins (Arc, PSD-95, and alpha-CaMKII) with key roles in long-term synaptic plasticity and long-term memory.

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Related in: MedlinePlus

Object recognition training induces an increase in the expression of Arc, α-CaMKII, and PSD-95 proteins in the dentate gyrus. Representative blots and comparisonof normalized protein levels of  (a) Arc, (b) α-CaMKII, and (c) PSD-95 proteins are presented for the C60 and L60 groups (relative to CC). Data arepresented as mean ± SEM (n = 7 for all groups). Protein levels were normalized toβ-actin. Asterisks indicate P ≤ .05.
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fig5: Object recognition training induces an increase in the expression of Arc, α-CaMKII, and PSD-95 proteins in the dentate gyrus. Representative blots and comparisonof normalized protein levels of (a) Arc, (b) α-CaMKII, and (c) PSD-95 proteins are presented for the C60 and L60 groups (relative to CC). Data arepresented as mean ± SEM (n = 7 for all groups). Protein levels were normalized toβ-actin. Asterisks indicate P ≤ .05.

Mentions: Western blot was used to assess the expression levels of Arc protein inthe DG of trained animals (Figure 5(a)). Arc levels were elevated more than2.5-fold in the L60 group compared with C60 (P = .05). Thislearning-associated increase matches the changes in Arc mRNA as revealed by in situ hybridization (Figure 3(d)). We then asked whether this increase inArc expression is paralleled by altered expression of other proteins involvedin synaptic plasticity and memory consolidation. For this purpose we chose twocore constituents of the postsynaptic density complex, the scaffolding proteinPSD-95 and the enzyme α-CaMKII. Bothproteins undergo local dendritic synthesis, regulate the structure and receptorcomposition of the PSD, and have important functions in synaptic plasticity andmemory [50–53, 58–61].Like Arc, α-CaMKII (Figure 5(b)) and PSD-95 (Figure 5(c)) were both upregulated inthe L60 group relative to the C60 group, which was exposed to the arena withoutobjects (P = .03 and P = .02). Another intriguing aspect of theprotein response was the decrease in expression of Arc and α-CaMKII in the C60group to as much as 50% of the caged controls, although this effect was notsignificant.


Object-place recognition learning triggers rapid induction of plasticity-related immediate early genes and synaptic proteins in the rat dentate gyrus.

Soulé J, Penke Z, Kanhema T, Alme MN, Laroche S, Bramham CR - Neural Plast. (2009)

Object recognition training induces an increase in the expression of Arc, α-CaMKII, and PSD-95 proteins in the dentate gyrus. Representative blots and comparisonof normalized protein levels of  (a) Arc, (b) α-CaMKII, and (c) PSD-95 proteins are presented for the C60 and L60 groups (relative to CC). Data arepresented as mean ± SEM (n = 7 for all groups). Protein levels were normalized toβ-actin. Asterisks indicate P ≤ .05.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2631155&req=5

fig5: Object recognition training induces an increase in the expression of Arc, α-CaMKII, and PSD-95 proteins in the dentate gyrus. Representative blots and comparisonof normalized protein levels of (a) Arc, (b) α-CaMKII, and (c) PSD-95 proteins are presented for the C60 and L60 groups (relative to CC). Data arepresented as mean ± SEM (n = 7 for all groups). Protein levels were normalized toβ-actin. Asterisks indicate P ≤ .05.
Mentions: Western blot was used to assess the expression levels of Arc protein inthe DG of trained animals (Figure 5(a)). Arc levels were elevated more than2.5-fold in the L60 group compared with C60 (P = .05). Thislearning-associated increase matches the changes in Arc mRNA as revealed by in situ hybridization (Figure 3(d)). We then asked whether this increase inArc expression is paralleled by altered expression of other proteins involvedin synaptic plasticity and memory consolidation. For this purpose we chose twocore constituents of the postsynaptic density complex, the scaffolding proteinPSD-95 and the enzyme α-CaMKII. Bothproteins undergo local dendritic synthesis, regulate the structure and receptorcomposition of the PSD, and have important functions in synaptic plasticity andmemory [50–53, 58–61].Like Arc, α-CaMKII (Figure 5(b)) and PSD-95 (Figure 5(c)) were both upregulated inthe L60 group relative to the C60 group, which was exposed to the arena withoutobjects (P = .03 and P = .02). Another intriguing aspect of theprotein response was the decrease in expression of Arc and α-CaMKII in the C60group to as much as 50% of the caged controls, although this effect was notsignificant.

Bottom Line: Here, we examined expression of the plasticity-associated immediate early genes (Arc, Zif268, and Narp) in the dentate gyrus following long-term object-place recognition learning in rats.RT-PCR analysis from dentate gyrus tissue collected shortly after training did not reveal learning-specific changes in Arc mRNA expression.Thus, object-place recognition triggers rapid, blade-specific upregulation of plasticity-associated immediate early genes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedicine and Bergen Mental Health Research Center, University of Bergen, Bergen, Norway.

ABSTRACT
Long-term recognition memory requires protein synthesis, but little is known about the coordinate regulation of specific genes. Here, we examined expression of the plasticity-associated immediate early genes (Arc, Zif268, and Narp) in the dentate gyrus following long-term object-place recognition learning in rats. RT-PCR analysis from dentate gyrus tissue collected shortly after training did not reveal learning-specific changes in Arc mRNA expression. In situ hybridization and immunohistochemistry were therefore used to assess possible sparse effects on gene expression. Learning about objects increased the density of granule cells expressing Arc, and to a lesser extent Narp, specifically in the dorsal blade of the dentate gyrus, while Zif268 expression was elevated across both blades. Thus, object-place recognition triggers rapid, blade-specific upregulation of plasticity-associated immediate early genes. Furthermore, Western blot analysis of dentate gyrus homogenates demonstrated concomitant upregulation of three postsynaptic density proteins (Arc, PSD-95, and alpha-CaMKII) with key roles in long-term synaptic plasticity and long-term memory.

Show MeSH
Related in: MedlinePlus