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Updated: Jun 20, 2026
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Long-term Potentiation of Perforant Pathway-dentate Gyrus Synapse in Freely Behaving Mice
Published on: November 29, 2013
Presynaptically expressed long-term potentiation increases multivesicular release at parallel fiber synapses
Vanessa A Bender1, Jason R Pugh, Craig E Jahr
1Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA.
Summary
Presynaptic long-term potentiation (LTP) at parallel fiber-molecular layer interneuron synapses increases multivesicular release (MVR). This suggests MVR occurs physiologically and is modulated by both short- and long-term plasticity.
Area of Science:
- Neuroscience
- Synaptic Plasticity
- Neurotransmission
Background:
- Long-term potentiation (LTP) enhances synaptic strength.
- Presynaptic LTP mechanisms, particularly regarding multivesicular release (MVR), remain unclear.
Purpose of the Study:
- To investigate if presynaptic LTP involves an increase in MVR at parallel fiber-molecular layer interneuron (PF-MLI) synapses.
- To determine if MVR occurs under baseline conditions and is modulated by plasticity.
Main Methods:
- Utilized AMPA receptor EPSCs and a low-affinity antagonist to assess glutamate concentration transients.
- Manipulated release probability (P(R)) using forskolin, extracellular Ca2+, and presynaptic adenosine receptors.
Main Results:
- Presynaptic LTP induction decreased antagonist inhibition, indicating larger glutamate transients and MVR.
- Increased P(R) mimicked this effect, while decreased P(R) increased inhibition, suggesting baseline MVR.
- MVR was confirmed to be modulated by both short- and long-term plasticity.
Conclusions:
- Multivesicular release (MVR) occurs at PF-MLI synapses under physiological conditions.
- Presynaptic LTP enhances MVR, demonstrating that long-term plasticity can modify MVR.
- Both short- and long-term plasticity mechanisms can increase MVR by elevating release probability.
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