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Differentiation in the protein synthesis-dependency of persistent synaptic plasticity in mossy fiber and associational/commissural CA3 synapses in vivo.

Hagena H, Manahan-Vaughan D - Front Integr Neurosci (2013)

Bottom Line: In contrast, at AC-CA3 synapses, translation inhibitors prevented intermediate/late-LTP and late-LTD only.Transcription effects were also synapse-specific: whereas transcription inhibitors inhibited late-LTP and late-LTD (>3 h) at mf-CA3 synapses, at AC-CA3 synapses, protein transcription affected early-LTP and late-LTD.These results show that the AC-CA3 and mf-CA3 synapses display different properties in terms of their protein synthesis dependency, suggesting different roles in the processing of short- and long term synaptic plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurophysiology, Medical Faculty, Ruhr University Bochum Bochum, Germany ; International Graduate School for Neuroscience, Ruhr University Bochum Bochum, Germany.

ABSTRACT
Long-term potentiation (LTP) and long-term depression (LTD) are two mechanisms involved in the long-term storage of information in hippocampal synapses. In the hippocampal CA1 region, the late phases of LTP and LTD are protein-synthesis dependent. In the dentate gyrus, late-LTP but not LTD requires protein synthesis. The protein synthesis-dependency of persistent plasticity at CA3 synapses has not yet been characterized. Here, the roles of protein transcription and translation at mossy fiber (mf) and associational/commissural (AC)- synapses were studied in freely behaving rats. In control animals, low-frequency stimulation (LFS) evoked robust LTD (>24 h), whereas high-frequency stimulation (HFS) elicited robust LTP (>24 h) at both mf-CA3 and AC-CA3 synapses. Translation inhibitors prevented early and late phases of LTP and LTD at mf-CA3 synapses. In contrast, at AC-CA3 synapses, translation inhibitors prevented intermediate/late-LTP and late-LTD only. Transcription effects were also synapse-specific: whereas transcription inhibitors inhibited late-LTP and late-LTD (>3 h) at mf-CA3 synapses, at AC-CA3 synapses, protein transcription affected early-LTP and late-LTD. These results show that the AC-CA3 and mf-CA3 synapses display different properties in terms of their protein synthesis dependency, suggesting different roles in the processing of short- and long term synaptic plasticity.

No MeSH data available.


Related in: MedlinePlus

Transcription inhibitors block early and late LTP, and late-LTD only, at associational/commissural–CA3 synapses. (A) In control experiments, application of HFS results in LTP (>24 h). Injection of actinomycin D inhibits the early and late phase of LTP. (B) Application of LFS results in the expression of LTD (>24 h). In the presence of actinomycin D, early and late phases of LTD are inhibited. (C) Injection of DRB inhibits the early and late phase of LTP compared to controls. (D) In the presence of DRB, early and late phases of LTD are inhibited compared to controls. Line breaks indicate change in time-scale. (E) Traces in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. (F) Traces depicted in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms.
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Figure 5: Transcription inhibitors block early and late LTP, and late-LTD only, at associational/commissural–CA3 synapses. (A) In control experiments, application of HFS results in LTP (>24 h). Injection of actinomycin D inhibits the early and late phase of LTP. (B) Application of LFS results in the expression of LTD (>24 h). In the presence of actinomycin D, early and late phases of LTD are inhibited. (C) Injection of DRB inhibits the early and late phase of LTP compared to controls. (D) In the presence of DRB, early and late phases of LTD are inhibited compared to controls. Line breaks indicate change in time-scale. (E) Traces in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. (F) Traces depicted in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms.

Mentions: In control animals, that received only vehicle injection, HFS or LFS led to LTP or LTD, respectively, that lasted for over 24 h (Figures 5A,B). Injection of actinomycin D, ipsilaterally, inhibited the early and late phase of LTP (ANOVA compared to vehicle-injected controls, F(1, 3) = 17.20; p = 0.02; interaction effect: p = 0.43, Figures 5A,E).


Differentiation in the protein synthesis-dependency of persistent synaptic plasticity in mossy fiber and associational/commissural CA3 synapses in vivo.

Hagena H, Manahan-Vaughan D - Front Integr Neurosci (2013)

Transcription inhibitors block early and late LTP, and late-LTD only, at associational/commissural–CA3 synapses. (A) In control experiments, application of HFS results in LTP (>24 h). Injection of actinomycin D inhibits the early and late phase of LTP. (B) Application of LFS results in the expression of LTD (>24 h). In the presence of actinomycin D, early and late phases of LTD are inhibited. (C) Injection of DRB inhibits the early and late phase of LTP compared to controls. (D) In the presence of DRB, early and late phases of LTD are inhibited compared to controls. Line breaks indicate change in time-scale. (E) Traces in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. (F) Traces depicted in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms.
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Figure 5: Transcription inhibitors block early and late LTP, and late-LTD only, at associational/commissural–CA3 synapses. (A) In control experiments, application of HFS results in LTP (>24 h). Injection of actinomycin D inhibits the early and late phase of LTP. (B) Application of LFS results in the expression of LTD (>24 h). In the presence of actinomycin D, early and late phases of LTD are inhibited. (C) Injection of DRB inhibits the early and late phase of LTP compared to controls. (D) In the presence of DRB, early and late phases of LTD are inhibited compared to controls. Line breaks indicate change in time-scale. (E) Traces in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or actinomycin D (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. (F) Traces depicted in the left panel represent fEPSP responses recorded pre-HFS (i), 5 min post-HFS (ii), and 24 h after HFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms. Analogs in the right panel represent fEPSP responses recorded pre-LFS (i), 5 min post-LFS (ii), and 24 h after LFS (iii) in the presence of vehicle (upper traces) or DRB (lower traces). Vertical scale bar: 2 mV, horizontal scale bar: 8 ms.
Mentions: In control animals, that received only vehicle injection, HFS or LFS led to LTP or LTD, respectively, that lasted for over 24 h (Figures 5A,B). Injection of actinomycin D, ipsilaterally, inhibited the early and late phase of LTP (ANOVA compared to vehicle-injected controls, F(1, 3) = 17.20; p = 0.02; interaction effect: p = 0.43, Figures 5A,E).

Bottom Line: In contrast, at AC-CA3 synapses, translation inhibitors prevented intermediate/late-LTP and late-LTD only.Transcription effects were also synapse-specific: whereas transcription inhibitors inhibited late-LTP and late-LTD (>3 h) at mf-CA3 synapses, at AC-CA3 synapses, protein transcription affected early-LTP and late-LTD.These results show that the AC-CA3 and mf-CA3 synapses display different properties in terms of their protein synthesis dependency, suggesting different roles in the processing of short- and long term synaptic plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurophysiology, Medical Faculty, Ruhr University Bochum Bochum, Germany ; International Graduate School for Neuroscience, Ruhr University Bochum Bochum, Germany.

ABSTRACT
Long-term potentiation (LTP) and long-term depression (LTD) are two mechanisms involved in the long-term storage of information in hippocampal synapses. In the hippocampal CA1 region, the late phases of LTP and LTD are protein-synthesis dependent. In the dentate gyrus, late-LTP but not LTD requires protein synthesis. The protein synthesis-dependency of persistent plasticity at CA3 synapses has not yet been characterized. Here, the roles of protein transcription and translation at mossy fiber (mf) and associational/commissural (AC)- synapses were studied in freely behaving rats. In control animals, low-frequency stimulation (LFS) evoked robust LTD (>24 h), whereas high-frequency stimulation (HFS) elicited robust LTP (>24 h) at both mf-CA3 and AC-CA3 synapses. Translation inhibitors prevented early and late phases of LTP and LTD at mf-CA3 synapses. In contrast, at AC-CA3 synapses, translation inhibitors prevented intermediate/late-LTP and late-LTD only. Transcription effects were also synapse-specific: whereas transcription inhibitors inhibited late-LTP and late-LTD (>3 h) at mf-CA3 synapses, at AC-CA3 synapses, protein transcription affected early-LTP and late-LTD. These results show that the AC-CA3 and mf-CA3 synapses display different properties in terms of their protein synthesis dependency, suggesting different roles in the processing of short- and long term synaptic plasticity.

No MeSH data available.


Related in: MedlinePlus