title: The mammalian central nervous synaptic cleft contains a high density of periodically organized complexes.
abstract: Cryo-electron microscopy of vitreous section makes it possible to observe cells and tissues at high resolution in a close-to-native state. The specimen remains hydrated; chemical fixation and staining are fully avoided. There is minimal molecular aggregation and the density observed in the image corresponds to the density in the object. Accordingly, organotypic hippocampal rat slices were vitrified under high pressure and controlled cryoprotection conditions, cryosectioned at a final thickness of approximately 70 nm and observed below -170 degrees C in a transmission electron microscope. The general aspect of the tissue compares with previous electron microscopy observations. The detailed analysis of the synapse reveals that the density of material in the synaptic cleft is high, even higher than in the cytoplasm, and that it is organized in 8.2-nm periodic transcleft complexes. Previously undescribed structures of presynaptic and postsynaptic elements are also described.
authors.affiliation: Laboratoire d'Analyse Ultrastructurale, Bâtiment de Biologie, Université de Lausanne, CH-1015 Lausanne, Switzerland. benoit-zuber@unil.ch
authors.forename: Benoît
authors.initials: B
authors.lastname: Zuber
authors.forename: Irina
authors.initials: I
authors.lastname: Nikonenko
authors.forename: Paul
authors.initials: P
authors.lastname: Klauser
authors.forename: Dominique
authors.initials: D
authors.lastname: Muller
authors.forename: Jacques
authors.initials: J
authors.lastname: Dubochet
mesh_terms: D000818:Animals; D001706:Biopsy; D002490:Central Nervous System / Q000473:pathology*; D020285:Cryoelectron Microscopy; D004594:Electrophysiology; D005615:Freezing; D006624:Hippocampus / Q000473:pathology*; D008854:Microscopy, Electron; D046529:Microscopy, Electron, Transmission; D009417:Nerve Tissue; D009420:Nervous System / Q000473:pathology; D017933:Peripheral Nervous System / Q000473:pathology; D011312:Pressure; D051381:Rats; D013569:Synapses; D013696:Temperature; D013997:Time Factors