ミドリカワ ミツハル
  緑川 光春
   所属   医学部 医学科
   職種   講師
論文種別 原著
言語種別 英語
査読の有無 査読あり
表題 Different roles of ribbon-associated and ribbon-free active zones in retinal bipolar cells.
掲載誌名 正式名:Nature neuroscience
略  称:Nat Neurosci
ISSNコード:(1097-6256)1097-6256(Linking)
掲載区分国外
巻・号・頁 10(10),1268-1276頁
著者・共著者 Midorikawa Mitsuharu, Tsukamoto Yoshihiko, Berglund Ken, Ishii Masaaki, Tachibana Masao
発行年月 2007/10
概要 Synaptic ribbons with a halo of synaptic vesicles are seen at the active zones of sensory neurons that release transmitter tonically. Thus, ribbons are assumed to be a prerequisite for sustained exocytosis. By applying total internal reflection fluorescence microscopy to goldfish retinal bipolar cell terminals, we visualized Ca2+ entry sites, ribbons, and vesicle fusion events. Here we show that the main Ca2+ entry sites were located at ribbons, and that activation of the Ca2+ current induced immediate and delayed vesicle fusion events at ribbon-associated and ribbon-free 'hot spots', respectively. The activation of protein kinase C (PKC) specifically potentiated vesicle fusion at ribbon-free sites. Electron microscopy showed that PKC activation selectively increased the number of docked vesicles at ribbon-free sites, which faced neuronal processes with the postsynaptic density. Retinal bipolar cells have both ribbon-associated and ribbon-free active zones in their terminals and might send functionally distinct signals through ribbon-associated and ribbon-free synapses to postsynaptic neurons.
DOI 10.1038/nn1963
PMID 17828257