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Context-Dependent Modulation of Excitatory Synaptic Strength by Synaptically Released Zinc.
Bopanna I Kalappa1, Thanos Tzounopoulos1
1Departments of Otolaryngology and Neurobiology, University of Pittsburgh , Pittsburgh, PA 15261.
Eneuro
|March 10, 2017
Summary
Synaptically released zinc modulates excitatory synaptic plasticity. It inhibits transmission at low activity but enhances it at high activity by potentiating synaptic facilitation.
Area of Science:
- Neuroscience
- Synaptic Plasticity
- Neuromodulation
Background:
- Synaptically released zinc is a neuromodulator affecting excitatory neurotransmission.
- Its role in short-term plasticity under varying synaptic activity levels is not well understood.
- This knowledge gap impacts understanding information transfer in zinc-releasing synapses, common in cortical areas.
Purpose of the Study:
- To investigate the context-dependent effects of synaptically released zinc on excitatory short-term plasticity.
- To elucidate the mechanisms underlying zinc's influence on synaptic plasticity at different activity levels.
Main Methods:
- Utilized in vitro electrophysiology in mouse brain slices.
- Measured excitatory postsynaptic current (EPSC) amplitudes under varying stimulation frequencies and release probabilities.
Main Results:
- Zinc's effect on EPSC amplitudes is context-dependent.
- At low frequencies, zinc reduces EPSC amplitudes.
- At high frequencies and release probabilities, zinc initially inhibits but then enhances steady-state EPSC amplitudes.
- This enhancement is mediated by zinc-dependent potentiation of synaptic facilitation via endocannabinoid signaling.
Conclusions:
- Synaptically released zinc acts as a modulator of excitatory short-term plasticity.
- Zinc dynamically shapes information transfer across excitatory synapses based on activity levels.
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