| Abstract
| - A liposome model of exocytosis has been used to examinethe nanometer environment of the space between theelectrode and the membrane. First, this has been usedto test models of coulometric efficiency for different sizevesicles with 5- and 33-μm electrodes. The resultingmodel has a best fit that suggests that the liquid space is∼300 nm across the gap. Given this dimension, thevolume of the electrode-membrane space is not largeenough to accommodate the volume of larger vesicles incells such as the mast cells of the beige mouse. Second,the model suggests that flow of solution from the exocytosis eventis more important than diffusion. Flow fromthe finite vesicle volume past the electrode leads to lesscharge passed. Third, and finally, this system can be usedto model transport in the synapse and so it is possible toexamine the idea that transmitter flows in addition todiffusing from the synapse. This model should be usefulin understanding and quantifying the escape of transmitterfrom synapses in vivo.
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