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Translational suppression of calpain blocks long-term potentiation
P Vanderklish1, E Bednarski, G Lynch
1Center for the Neurobiology of Learning and Memory, University of California at Irvine 92717, USA.
Abstract:
Transfection with antisense oligonucleotides was used to reduce calpain 1 activity to approximately 50% of normal values in cultured hippocampal slices. This had no detectable effects on baseline synaptic responses but greatly reduced the incidence and magnitude of long-term potentiation induced with a theta-burst stimulation paradigm. These results suggest that activation of calpain by repetitive bursts of afferent activity, as shown to occur in prior studies, is an essential step in the production of stable increases in synaptic strength.
Insights
Reducing calpain 1 activity in brain slices did not affect baseline responses but significantly impaired long-term potentiation. This suggests calpain activation is essential for strengthening synaptic connections.
Area of Science:
- Neuroscience
- Molecular Biology
- Synaptic Plasticity
Background:
- Calpains are calcium-dependent proteases implicated in various cellular processes.
- Synaptic plasticity, the ability of synapses to strengthen or weaken over time, is crucial for learning and memory.
- Repetitive neuronal activity can activate calpains in the hippocampus.
Purpose of the Study:
- To investigate the role of calpain 1 in synaptic plasticity, specifically long-term potentiation (LTP).
- To determine if inhibiting calpain 1 affects baseline synaptic transmission or the induction of LTP.
Main Methods:
- Cultured hippocampal slices were used as the experimental model.
- Antisense oligonucleotides were employed to specifically reduce calpain 1 activity by approximately 50%.
- Synaptic responses were measured, and LTP was induced using a theta-burst stimulation paradigm.
Main Results:
- Reduced calpain 1 activity had no discernible impact on baseline synaptic responses.
- The incidence and magnitude of theta-burst stimulation-induced LTP were significantly diminished in slices with reduced calpain 1 activity.
- These findings indicate a critical role for calpain 1 in the stabilization of synaptic strength.
Conclusions:
- Calpain 1 activation, triggered by repetitive afferent activity, is a necessary step for establishing stable increases in synaptic strength.
- Calpain 1 is essential for the molecular mechanisms underlying long-term potentiation in the hippocampus.
- Targeting calpain activity may offer insights into modulating synaptic plasticity and related cognitive functions.