1. Membrane cholesterol regulates different modes of synaptic vesicle release and retrieval at the frog neuromuscular junction.
- Author
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Rodrigues HA, Lima RF, Fonseca Mde C, Amaral EA, Martinelli PM, Naves LA, Gomez MV, Kushmerick C, Prado MA, and Guatimosim C
- Subjects
- Animals, Cell Membrane drug effects, Exocytosis drug effects, Exocytosis physiology, Microelectrodes, Microscopy, Electron, Transmission, Microscopy, Fluorescence, Miniature Postsynaptic Potentials drug effects, Miniature Postsynaptic Potentials physiology, Neuromuscular Agents pharmacology, Neuromuscular Junction drug effects, Neuromuscular Junction ultrastructure, Potassium Chloride pharmacology, Pyridinium Compounds, Quaternary Ammonium Compounds, Rana catesbeiana, Receptors, Nicotinic metabolism, Synaptic Vesicles drug effects, Synaptic Vesicles ultrastructure, Tissue Culture Techniques, beta-Cyclodextrins pharmacology, Cell Membrane physiology, Cholesterol metabolism, Neuromuscular Junction physiology, Synaptic Vesicles physiology
- 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., (© 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)
- Published
- 2013
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