title: Membrane cholesterol regulates different modes of synaptic vesicle release and retrieval at the frog neuromuscular junction.
abstract: We investigated the effects of cholesterol removal on spontaneous and KCl-evoked synaptic vesicle recycling at the frog neuromuscular junction. Cholesterol removal by methyl-β-cyclodextrin (MβCD) induced an increase in the frequency of miniature end-plate potentials (MEPPs) and spontaneous destaining of synaptic vesicles labeled with the styryl dye FM1-43. Treatment with MβCD also increased the size of MEPPs without causing significant changes in nicotinic receptor clustering. At the ultrastructural level, synaptic vesicles from nerve terminals treated with MβCD were larger than those from control. In addition, treatment with MβCD reduced the fusion of synaptic vesicles that are mobilized during KCl-evoked stimulation, but induced recycling of those vesicles that fuse spontaneously. We therefore suggest that MβCD might favor the release of vesicles that belong to a pool that is different from that involved in the KCl-evoked release. These results reveal fundamental differences in the synaptic vesicle cycle for spontaneous and evoked release, and suggest that deregulation of cholesterol affects synaptic vesicle biogenesis and increases transmitter packing.
authors.affiliation: Departamento de Morfologia, Universidade Federal de Minas Gerais, Av Antônio Carlos 6627, Belo Horizonte, MG 31270-901, Brasil.
authors.forename: Hermann A
authors.initials: HA
authors.lastname: Rodrigues
authors.affiliation: Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: Ricardo F
authors.initials: RF
authors.lastname: Lima
authors.affiliation: Departamento de Morfologia, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brasil.
authors.forename: Matheus de C
authors.initials: Mde C
authors.lastname: Fonseca
authors.affiliation: Departamento de Morfologia, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brasil.
authors.forename: Ernani A
authors.initials: EA
authors.lastname: Amaral
authors.affiliation: Departamento de Morfologia, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brasil.
authors.forename: Patrícia M
authors.initials: PM
authors.lastname: Martinelli
authors.affiliation: Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: Lígia A
authors.initials: LA
authors.lastname: Naves
authors.affiliation: Núcleo Santa Casa de Pós-Graduação, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.|INCT Molecular Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: Marcus V
authors.initials: MV
authors.lastname: Gomez
authors.affiliation: Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kushmerick
authors.affiliation: Robarts Research Institute and Department of Physiology and Pharmacology and Anatomy & Cell Biology, University of Western Ontario, London, ON, Canada.
authors.forename: Marco A M
authors.initials: MA
authors.lastname: Prado
authors.affiliation: Departamento de Morfologia, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brasil.
authors.forename: Cristina
authors.initials: C
authors.lastname: Guatimosim
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D002784:Cholesterol / Q000378:metabolism*; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology; D008839:Microelectrodes; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D055369:Miniature Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D009465:Neuromuscular Agents / Q000494:pharmacology; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D011189:Potassium Chloride / Q000494:pharmacology; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D011892:Rana catesbeiana; D011978:Receptors, Nicotinic / Q000378:metabolism; D013572:Synaptic Vesicles / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D046509:Tissue Culture Techniques; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: C073804:FM1 43; D009465:Neuromuscular Agents; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D011978:Receptors, Nicotinic; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D011189:Potassium Chloride; D002784:Cholesterol
keywords: FM1-43; cholesterol; fluorescence microscopy; neuromuscular junction; synaptic vesicle