Three modes of synaptic vesicular recycling revealed by single-vesicle imaging.
Synapses recycle their spent vesicles in order to keep up with on-going neurotransmitter release. To investigate vesicle recycling in the small synapses of hippocampal neurons, we have used an optical recording method that permits us to resolve single-vesicle events. Here we show that an exocytic event can terminate with three modes of vesicle retrieval: a fast (400-860 ms) 'kiss-and-run' mode that has a selective fusion pore; a slow (8-21 s) 'compensatory' mode; and a 'stranded' mode of recycling, in which a vesicle is left on the cell surface until a nerve impulse triggers its retrieval. We have also observed that, in response to a nerve impulse, synapses with low release probability primarily use the kiss-and-run mode, whereas high release probability terminals predominantly use the compensatory mode of vesicle retrieval.
Gandhi
Sunil P
SP
Neurosciences Program, University of California, San Diego, La Jolla, California 92093, USA.
Stevens
Charles F
CF
D000143:Acids; D000818:Animals; D000831:Animals, Newborn; D002021:Buffers; D002478:Cells, Cultured; D004705:Endocytosis; D005071:Evoked Potentials / Q000502:physiology; D005089:Exocytosis; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D017729:Presynaptic Terminals / Q000378:metabolism; D011336:Probability; D017966:Pyramidal Cells / Q000166:cytology / Q000502:physiology; D051381:Rats; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000378:metabolism*; D013997:Time Factors
D000143:Acids; D002021:Buffers