Conical electron tomography of a chemical synapse: polyhedral cages dock vesicles to the active zone.

ABSTRACT: In this study, we tested the hypothesis that the structure of the active zone of chemical synapses has remained uncertain because of limitations of conventional electron microscopy. To resolve these limitations, we reconstructed chemical synapses of rat neocortex, the archetypical "average" synapse, by conical electron tomography, a method that exhibits an isotropic in plane resolution of approximately 3 nm and eliminates the need to impose symmetry or use averaging methods to increase signal-to-noise ratios. Analysis of 17 reconstructions by semiautomatic density segmentation indicated that the active zone was constructed of a variable number of distinct "synaptic units" comprising a polyhedral cage and a corona of approximately seven vesicles. The polyhedral cages measured approximately

SUBMITTER: Zampighi GA 

PROVIDER: S-EPMC3844767 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature