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Synaptic vesicle transporter expression regulates vesicle phenotype and quantal size.
E N Pothos1, K E Larsen, D E Krantz
1Departments of Neurology and Psychiatry, Columbia University, New York, New York 10032, USA.
Summary
Overexpressing the brain vesicular monoamine transporter 2 (VMAT2) enhances dopamine release by increasing quantal size and frequency. This reveals how transporter expression regulates synaptic strength.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Synaptic vesicle transporters are crucial for neurotransmitter accumulation.
- The regulatory role of transporter expression in synaptic transmission remains largely unknown.
Purpose of the Study:
- To investigate how brain vesicular monoamine transporter 2 (VMAT2) expression influences quantal release and synaptic transmission.
- To elucidate the mechanisms by which VMAT2 affects synaptic strength.
Main Methods:
- Adenoviral-mediated transfection to overexpress VMAT2 in neurons.
- Presynaptic amperometric recordings to measure quantal release.
- Utilized ventral midbrain neurons, AtT-20 cells, and PC12 cells.
Main Results:
- VMAT2 overexpression in small synaptic vesicles increased both quantal size and frequency in ventral midbrain neurons.
- VMAT2 expression induced dopamine quantal release in noncatecholaminergic AtT-20 cells.
- In PC12 cells, VMAT2 increased quantal size without altering the number of release events.
Conclusions:
- Vesicle transporters, like VMAT2, limit the rate of neurotransmitter accumulation.
- VMAT2 expression can alter synaptic strength through distinct mechanisms, affecting both vesicle recruitment and content.