Experience-dependent formation and recruitment of large vesicles from reserve pool.
The sizes and contents of transmitter-filled vesicles have been shown to vary depending on experimental manipulations resulting in altered quantal sizes. However, whether such a presynaptic regulation of quantal size can be induced under physiological conditions as a potential alternative mechanism to alter the strength of synaptic transmission is unknown. Here we show that presynaptic vesicles of glutamatergic synapses of Drosophila neuromuscular junctions increase in size as a result of high natural crawling activities of larvae, leading to larger quantal sizes and enhanced evoked synaptic transmission. We further show that these larger vesicles are formed during a period of enhanced replenishment of the reserve pool of vesicles, from which they are recruited via a PKA- and actin-dependent mechanism. Our results demonstrate that natural behavior can induce the formation, recruitment, and release of larger vesicles in an experience-dependent manner and hence provide evidence for an additional mechanism of synaptic potentiation.
Steinert
Joern R
JR
Department of Neurobiology, Interdisciplinary Center for Neurosciences, University of Heidelberg, 69120 Heidelberg, Germany.
Kuromi
Hiroshi
H
Hellwig
Andrea
A
Knirr
Matthias
M
Wyatt
Amanda W
AW
Kidokoro
Yoshiaki
Y
Schuster
Christoph M
CM
D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila / Q000502:physiology*; D015870:Gene Expression; D049452:Green Fluorescent Proteins / Q000235:genetics; D007814:Larva / Q000502:physiology; D008124:Locomotion / Q000502:physiology*; D008854:Microscopy, Electron; D009469:Neuromuscular Junction / Q000502:physiology* / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000502:physiology / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000502:physiology*; D013572:Synaptic Vesicles / Q000502:physiology* / Q000648:ultrastructure; D050496:Vesicular Glutamate Transport Proteins / Q000235:genetics / Q000378:metabolism
D050496:Vesicular Glutamate Transport Proteins; D049452:Green Fluorescent Proteins