title: Ultrafast endocytosis at Caenorhabditis elegans neuromuscular junctions.
abstract: Synaptic vesicles can be released at extremely high rates, which places an extraordinary demand on the recycling machinery. Previous ultrastructural studies of vesicle recycling were conducted in dissected preparations using an intense stimulation to maximize the probability of release. Here, a single light stimulus was applied to motor neurons in intact Caenorhabditis elegans nematodes expressing channelrhodopsin, and the animals rapidly frozen. We found that docked vesicles fuse along a broad active zone in response to a single stimulus, and are replenished with a time constant of about 2 s. Endocytosis occurs within 50 ms adjacent to the dense projection and after 1 s adjacent to adherens junctions. These studies suggest that synaptic vesicle endocytosis may occur on a millisecond time scale following a single physiological stimulus in the intact nervous system and is unlikely to conform to current models of endocytosis. DOI:http://dx.doi.org/10.7554/eLife.00723.001.
authors.affiliation: Department of Biology , Howard Hughes Medical Institute, University of Utah , Salt Lake City , United States.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Watanabe
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: M Wayne
authors.initials: MW
authors.lastname: Davis
authors.forename: Gunther
authors.initials: G
authors.lastname: Hollopeter
authors.forename: Nikita
authors.initials: N
authors.lastname: Thomas
authors.forename: Nels B
authors.initials: NB
authors.lastname: Jorgensen
authors.forename: Erik M
authors.initials: EM
authors.lastname: Jorgensen
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism*; D004705:Endocytosis; D009469:Neuromuscular Junction / Q000378:metabolism*
keywords: C. elegans; active zone; high-pressure freezing; optogenetics; synaptic vesicle endocytosis; synaptic vesicle exocytosis; time-resolved electron microscopy