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The regulation of quantal size.
1Department of Physiology and Biophysics, SUNY, Stony Brook 11794.
Progress in Neurobiology
|January 1, 1991
Summary
Neuron regulation of quantal size is key, as experiments show synaptic vesicle transmitter capacity can be increased or decreased. Enhanced quantal output, signaled by increased release rate, upregulates quantal size.
Area of Science:
- Neuroscience
- Cell Biology
Background:
- Quantal size, the amount of neurotransmitter released in a single synaptic vesicle, can be experimentally altered.
- Previous assumptions suggested a fixed transmitter capacity per vesicle, but this is now challenged.
Purpose of the Study:
- To investigate the regulatory mechanisms controlling quantal size.
- To identify signals that upregulate quantal size in neurons.
Main Methods:
- Experimental manipulation of synaptic vesicle populations.
- Analysis of neurotransmitter release at the neuromuscular junction (NMJ) and other synapses.
- Exposure to hypertonic solutions and tetanic stimulation to alter quantal release rates.
Main Results:
- Quantal size is not fixed and can be regulated by the neuron.
- Presynaptic neuron stimulation increases quantal size at NMJ, autonomic ganglia, and hippocampus.
- Exposure to hypertonic solutions and tetanic stimulation upregulate quantal size, suggesting release rate is a key signal.
Conclusions:
- Quantal size is under neuronal regulation, allowing for adjustments in transmitter packaging.
- Increased quantal release rate serves as a signal for upregulating quantal size.
- Further research is needed to fully understand the pathways involved in quantal size regulation.