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A single fear-inducing stimulus induces a transcription-dependent switch in synaptic AMPAR phenotype.

Liu Y, Formisano L, Savtchouk I, Takayasu Y, Szabó G, Zukin RS, Liu SJ - Nat. Neurosci. (2009)

Bottom Line: The subsequent rise in intracellular Ca(2+) and activation of Ca(2+)-sensitive ERK/MAPK signaling triggered new GluR2 gene transcription and a switch in the synaptic AMPAR phenotype from GluR2-lacking, Ca(2+)-permeable receptors to GluR2-containing, Ca(2+)-impermeable receptors on the order of hours.The change in glutamate receptor phenotype altered synaptic efficacy in cerebellar stellate cells.Thus, a single fear-inducing stimulus can induce a long-term change in synaptic receptor phenotype and may alter the activity of an inhibitory neural network.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Pennsylvania State University, University Park, Pennsylvania, USA.

ABSTRACT
Changes in emotional state are known to alter neuronal excitability and can modify learning and memory formation. Such experience-dependent neuronal plasticity can be long-lasting and is thought to involve the regulation of gene transcription. We found that a single fear-inducing stimulus increased GluR2 (also known as Gria2) mRNA abundance and promoted synaptic incorporation of GluR2-containing AMPA receptors (AMPARs) in mouse cerebellar stellate cells. The switch in synaptic AMPAR phenotype was mediated by noradrenaline and action potential prolongation. The subsequent rise in intracellular Ca(2+) and activation of Ca(2+)-sensitive ERK/MAPK signaling triggered new GluR2 gene transcription and a switch in the synaptic AMPAR phenotype from GluR2-lacking, Ca(2+)-permeable receptors to GluR2-containing, Ca(2+)-impermeable receptors on the order of hours. The change in glutamate receptor phenotype altered synaptic efficacy in cerebellar stellate cells. Thus, a single fear-inducing stimulus can induce a long-term change in synaptic receptor phenotype and may alter the activity of an inhibitory neural network.

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Noradrenaline and TEA treatment increased the level of GluR2, but not GluR1 mRNA expression (n = 5). A–H. DIG-labeled RNA antisense probes for GluR1 and GluR2 mRNA (A–C; E–H) or the sense probes (D) were used. A and E. Control. B and C. noradrenaline treatment increased the level of GluR2 mRNA expression and actinomycin D (Act D) blocked the NA-induced increase in GluR2 expression. F. TEA treatment increased the level of GluR2, but not GluR1 mRNA expression. G and H. Actinomycin D (Act D) and U0126 prevented the TEA-induced increase in GluR2 mRNA expression in stellate cells. ML, molecular layer; PL, Purkinje cell layer; GL, granule cell layer; KYNA, kynurenic acid; picrotoxin, picrotoxin. The labeling that has intensity higher than background within an outline of typical stellate cells (~ 8 µm) was selected as regions of interest. Images are typical of n = 5 in each group. I, G and K. The number of labeled stellate cells that express high level of GluR2 mRNA under each condition relative to control. We used the mean of background intensity plus two standard deviations as threshold for positive labeling. (*, P < 0.05, by unpaired Student’s t-test). L, M and N. Cumulative distribution of the labeling intensity of selected regions of interest after background subtraction illustrated the changes in staining intensities of positive stained cells under each treatment condition (the number of ROIs ranged from 104 to 365 under each condition; noradrenaline vs. control or noradrenaline + Act D, TEA vs. control, or TEA + Act D, or TEA + U0126, Kolmogorov-Smirnov test, P < 0.0001). Scale bars, 200 µM (left panels), and 50 µM (right panels).
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Figure 7: Noradrenaline and TEA treatment increased the level of GluR2, but not GluR1 mRNA expression (n = 5). A–H. DIG-labeled RNA antisense probes for GluR1 and GluR2 mRNA (A–C; E–H) or the sense probes (D) were used. A and E. Control. B and C. noradrenaline treatment increased the level of GluR2 mRNA expression and actinomycin D (Act D) blocked the NA-induced increase in GluR2 expression. F. TEA treatment increased the level of GluR2, but not GluR1 mRNA expression. G and H. Actinomycin D (Act D) and U0126 prevented the TEA-induced increase in GluR2 mRNA expression in stellate cells. ML, molecular layer; PL, Purkinje cell layer; GL, granule cell layer; KYNA, kynurenic acid; picrotoxin, picrotoxin. The labeling that has intensity higher than background within an outline of typical stellate cells (~ 8 µm) was selected as regions of interest. Images are typical of n = 5 in each group. I, G and K. The number of labeled stellate cells that express high level of GluR2 mRNA under each condition relative to control. We used the mean of background intensity plus two standard deviations as threshold for positive labeling. (*, P < 0.05, by unpaired Student’s t-test). L, M and N. Cumulative distribution of the labeling intensity of selected regions of interest after background subtraction illustrated the changes in staining intensities of positive stained cells under each treatment condition (the number of ROIs ranged from 104 to 365 under each condition; noradrenaline vs. control or noradrenaline + Act D, TEA vs. control, or TEA + Act D, or TEA + U0126, Kolmogorov-Smirnov test, P < 0.0001). Scale bars, 200 µM (left panels), and 50 µM (right panels).

Mentions: We next examined whether noradrenaline increases the expression of GluR2 mRNA in stellate cells. Toward this end, we incubated acute rat cerebellar slices in noradrenaline (3 h, with kynurenic acid and picrotoxin) and then processed cerebellar sections for in situ hybridization. Noradrenaline markedly increased the number of cells expressing GluR2 mRNA and intensity of GluR2 mRNA expression in individual cells within the molecular layer (Fig. 7A,B,I,L). Actinomycin D prevented the noradrenaline-induced increase in GluR2 mRNA (Fig. 7C,I,L). At this age (P18–21), the vast majority of neurons in the molecular layer of the cerebellar cortex are inhibitory basket/stellate cells, which express parvalbumin (Fig. S4). These data indicate that noradrenaline acts via transcription of new GluR2 mRNA to increase the number of GluR2-containing AMPARs at parallel fibre-stellate cell synapses.


A single fear-inducing stimulus induces a transcription-dependent switch in synaptic AMPAR phenotype.

Liu Y, Formisano L, Savtchouk I, Takayasu Y, Szabó G, Zukin RS, Liu SJ - Nat. Neurosci. (2009)

Noradrenaline and TEA treatment increased the level of GluR2, but not GluR1 mRNA expression (n = 5). A–H. DIG-labeled RNA antisense probes for GluR1 and GluR2 mRNA (A–C; E–H) or the sense probes (D) were used. A and E. Control. B and C. noradrenaline treatment increased the level of GluR2 mRNA expression and actinomycin D (Act D) blocked the NA-induced increase in GluR2 expression. F. TEA treatment increased the level of GluR2, but not GluR1 mRNA expression. G and H. Actinomycin D (Act D) and U0126 prevented the TEA-induced increase in GluR2 mRNA expression in stellate cells. ML, molecular layer; PL, Purkinje cell layer; GL, granule cell layer; KYNA, kynurenic acid; picrotoxin, picrotoxin. The labeling that has intensity higher than background within an outline of typical stellate cells (~ 8 µm) was selected as regions of interest. Images are typical of n = 5 in each group. I, G and K. The number of labeled stellate cells that express high level of GluR2 mRNA under each condition relative to control. We used the mean of background intensity plus two standard deviations as threshold for positive labeling. (*, P < 0.05, by unpaired Student’s t-test). L, M and N. Cumulative distribution of the labeling intensity of selected regions of interest after background subtraction illustrated the changes in staining intensities of positive stained cells under each treatment condition (the number of ROIs ranged from 104 to 365 under each condition; noradrenaline vs. control or noradrenaline + Act D, TEA vs. control, or TEA + Act D, or TEA + U0126, Kolmogorov-Smirnov test, P < 0.0001). Scale bars, 200 µM (left panels), and 50 µM (right panels).
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Figure 7: Noradrenaline and TEA treatment increased the level of GluR2, but not GluR1 mRNA expression (n = 5). A–H. DIG-labeled RNA antisense probes for GluR1 and GluR2 mRNA (A–C; E–H) or the sense probes (D) were used. A and E. Control. B and C. noradrenaline treatment increased the level of GluR2 mRNA expression and actinomycin D (Act D) blocked the NA-induced increase in GluR2 expression. F. TEA treatment increased the level of GluR2, but not GluR1 mRNA expression. G and H. Actinomycin D (Act D) and U0126 prevented the TEA-induced increase in GluR2 mRNA expression in stellate cells. ML, molecular layer; PL, Purkinje cell layer; GL, granule cell layer; KYNA, kynurenic acid; picrotoxin, picrotoxin. The labeling that has intensity higher than background within an outline of typical stellate cells (~ 8 µm) was selected as regions of interest. Images are typical of n = 5 in each group. I, G and K. The number of labeled stellate cells that express high level of GluR2 mRNA under each condition relative to control. We used the mean of background intensity plus two standard deviations as threshold for positive labeling. (*, P < 0.05, by unpaired Student’s t-test). L, M and N. Cumulative distribution of the labeling intensity of selected regions of interest after background subtraction illustrated the changes in staining intensities of positive stained cells under each treatment condition (the number of ROIs ranged from 104 to 365 under each condition; noradrenaline vs. control or noradrenaline + Act D, TEA vs. control, or TEA + Act D, or TEA + U0126, Kolmogorov-Smirnov test, P < 0.0001). Scale bars, 200 µM (left panels), and 50 µM (right panels).
Mentions: We next examined whether noradrenaline increases the expression of GluR2 mRNA in stellate cells. Toward this end, we incubated acute rat cerebellar slices in noradrenaline (3 h, with kynurenic acid and picrotoxin) and then processed cerebellar sections for in situ hybridization. Noradrenaline markedly increased the number of cells expressing GluR2 mRNA and intensity of GluR2 mRNA expression in individual cells within the molecular layer (Fig. 7A,B,I,L). Actinomycin D prevented the noradrenaline-induced increase in GluR2 mRNA (Fig. 7C,I,L). At this age (P18–21), the vast majority of neurons in the molecular layer of the cerebellar cortex are inhibitory basket/stellate cells, which express parvalbumin (Fig. S4). These data indicate that noradrenaline acts via transcription of new GluR2 mRNA to increase the number of GluR2-containing AMPARs at parallel fibre-stellate cell synapses.

Bottom Line: The subsequent rise in intracellular Ca(2+) and activation of Ca(2+)-sensitive ERK/MAPK signaling triggered new GluR2 gene transcription and a switch in the synaptic AMPAR phenotype from GluR2-lacking, Ca(2+)-permeable receptors to GluR2-containing, Ca(2+)-impermeable receptors on the order of hours.The change in glutamate receptor phenotype altered synaptic efficacy in cerebellar stellate cells.Thus, a single fear-inducing stimulus can induce a long-term change in synaptic receptor phenotype and may alter the activity of an inhibitory neural network.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Pennsylvania State University, University Park, Pennsylvania, USA.

ABSTRACT
Changes in emotional state are known to alter neuronal excitability and can modify learning and memory formation. Such experience-dependent neuronal plasticity can be long-lasting and is thought to involve the regulation of gene transcription. We found that a single fear-inducing stimulus increased GluR2 (also known as Gria2) mRNA abundance and promoted synaptic incorporation of GluR2-containing AMPA receptors (AMPARs) in mouse cerebellar stellate cells. The switch in synaptic AMPAR phenotype was mediated by noradrenaline and action potential prolongation. The subsequent rise in intracellular Ca(2+) and activation of Ca(2+)-sensitive ERK/MAPK signaling triggered new GluR2 gene transcription and a switch in the synaptic AMPAR phenotype from GluR2-lacking, Ca(2+)-permeable receptors to GluR2-containing, Ca(2+)-impermeable receptors on the order of hours. The change in glutamate receptor phenotype altered synaptic efficacy in cerebellar stellate cells. Thus, a single fear-inducing stimulus can induce a long-term change in synaptic receptor phenotype and may alter the activity of an inhibitory neural network.

Show MeSH
Related in: MedlinePlus