title: Nanoscale distribution of presynaptic Ca(2+) channels and its impact on vesicular release during development.
abstract: Synaptic efficacy and precision are influenced by the coupling of voltage-gated Ca(2+) channels (VGCCs) to vesicles. But because the topography of VGCCs and their proximity to vesicles is unknown, a quantitative understanding of the determinants of vesicular release at nanometer scale is lacking. To investigate this, we combined freeze-fracture replica immunogold labeling of Cav2.1 channels, local [Ca(2+)] imaging, and patch pipette perfusion of EGTA at the calyx of Held. Between postnatal day 7 and 21, VGCCs formed variable sized clusters and vesicular release became less sensitive to EGTA, whereas fixed Ca(2+) buffer properties remained constant. Experimentally constrained reaction-diffusion simulations suggest that Ca(2+) sensors for vesicular release are located at the perimeter of VGCC clusters (<30 nm) and predict that VGCC number per cluster determines vesicular release probability without altering release time course. This "perimeter release model" provides a unifying framework accounting for developmental changes in both synaptic efficacy and time course.
authors.affiliation: Laboratory of Molecular Synaptic Function, Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan; Cellular & Molecular Synaptic Function Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, Okinawa 904-0495, Japan; Laboratory of Dynamic Neuronal Imaging, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France; CNRS UMR 3571, 25 rue du Dr Roux, 75724 Paris Cedex 15, France.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Division of Cerebral Structure, Department of Cerebral Research, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8787, Japan; Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria.
authors.forename: Harumi
authors.initials: H
authors.lastname: Harada
authors.affiliation: Division of Cerebral Structure, Department of Cerebral Research, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Kamasawa
authors.affiliation: Division of Cerebral Structure, Department of Cerebral Research, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Matsui
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street London WC1E 6BT, UK.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Rothman
authors.affiliation: Division of Cerebral Structure, Department of Cerebral Research, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8787, Japan; Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Shigemoto
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street London WC1E 6BT, UK.
authors.forename: R Angus
authors.initials: RA
authors.lastname: Silver
authors.affiliation: Laboratory of Dynamic Neuronal Imaging, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France; CNRS UMR 3571, 25 rue du Dr Roux, 75724 Paris Cedex 15, France. Electronic address: david.digregorio@pasteur.fr.
authors.forename: David A
authors.initials: DA
authors.lastname: DiGregorio
authors.affiliation: Laboratory of Molecular Synaptic Function, Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan; Cellular & Molecular Synaptic Function Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, Okinawa 904-0495, Japan. Electronic address: ttakahas@mail.doshisha.ac.jp.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020864:Calcium Channels, N-Type / Q000187:drug effects / Q000378:metabolism*; D065096:Calcium Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D013569:Synapses / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000378:metabolism*
chemical_list: D002118:Calcium; D020864:Calcium Channels, N-Type; D065096:Calcium Chelating Agents; D004533:Egtazic Acid