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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

Performance at the 2-day and 3-day retentionintervals of the object-place recognition memory task. At both (a) 2-day and (b) 3-day  delays after acquisition, rats (n = 15 in each case) showedpreferential exploration of the displaced object. (c) Schematic representationof the task. Asterisks indicate P ≤ .05 compared with chance level(dashed line, 33.3%). Data are presented as mean ± SEM.
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fig1: Performance at the 2-day and 3-day retentionintervals of the object-place recognition memory task. At both (a) 2-day and (b) 3-day delays after acquisition, rats (n = 15 in each case) showedpreferential exploration of the displaced object. (c) Schematic representationof the task. Asterisks indicate P ≤ .05 compared with chance level(dashed line, 33.3%). Data are presented as mean ± SEM.

Mentions: The training procedure involved habituation to the test arena, followedby exposure to three objects at fixed locations on four consecutive 5-minutesessions with 5-minute intervals (acquisition phase), and a retention test,which was performed 2 or 3 days later. In the retention test, one of theobjects was displaced and the amount of time exploring the displaced objectrelative to the total time of object exploration was determined. This paradigmhas been previously shown to induce long-term memory for objects andlocation of objects [44]. During the acquisition phase,ANOVA did not show significant differences between the time spent exploring the three objects(time spent exploring the three objects for the 2-day delay: 33.0 ± 2.0%,38.9 ± 2.2%, 28.1 ± 1.3% of total time; F2,42 = 0.90, P = .41, for the 3-daydelay: 32.7 ± 1.5%, 21.1 ± 1.2%, 46.2 ± 1.4% of total time; F2,42 = 2.68, P = .08). Duringretention testing, rats spent significantly more time exploringthe displaced object than chance level (33.33%) at both the 2 and 3-dayretention intervals (time spent exploring the displaced object for the 2-daydelay: 45.9 ± 1.3%of total time; t14 = 3.27, P < .01; for the 3-daydelay: 39.3 ± 2.3%of total time; t14 = 2.54, P < .05), as shown inFigures 1(a) and 1(b). This behavioral analysis shows that rats in our experimentalconditions were able to form a long-term object-place recognition memory.


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)

Performance at the 2-day and 3-day retentionintervals of the object-place recognition memory task. At both (a) 2-day and (b) 3-day  delays after acquisition, rats (n = 15 in each case) showedpreferential exploration of the displaced object. (c) Schematic representationof the task. Asterisks indicate P ≤ .05 compared with chance level(dashed line, 33.3%). Data are presented as mean ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig1: Performance at the 2-day and 3-day retentionintervals of the object-place recognition memory task. At both (a) 2-day and (b) 3-day delays after acquisition, rats (n = 15 in each case) showedpreferential exploration of the displaced object. (c) Schematic representationof the task. Asterisks indicate P ≤ .05 compared with chance level(dashed line, 33.3%). Data are presented as mean ± SEM.
Mentions: The training procedure involved habituation to the test arena, followedby exposure to three objects at fixed locations on four consecutive 5-minutesessions with 5-minute intervals (acquisition phase), and a retention test,which was performed 2 or 3 days later. In the retention test, one of theobjects was displaced and the amount of time exploring the displaced objectrelative to the total time of object exploration was determined. This paradigmhas been previously shown to induce long-term memory for objects andlocation of objects [44]. During the acquisition phase,ANOVA did not show significant differences between the time spent exploring the three objects(time spent exploring the three objects for the 2-day delay: 33.0 ± 2.0%,38.9 ± 2.2%, 28.1 ± 1.3% of total time; F2,42 = 0.90, P = .41, for the 3-daydelay: 32.7 ± 1.5%, 21.1 ± 1.2%, 46.2 ± 1.4% of total time; F2,42 = 2.68, P = .08). Duringretention testing, rats spent significantly more time exploringthe displaced object than chance level (33.33%) at both the 2 and 3-dayretention intervals (time spent exploring the displaced object for the 2-daydelay: 45.9 ± 1.3%of total time; t14 = 3.27, P < .01; for the 3-daydelay: 39.3 ± 2.3%of total time; t14 = 2.54, P < .05), as shown inFigures 1(a) and 1(b). This behavioral analysis shows that rats in our experimentalconditions were able to form a long-term object-place recognition memory.

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