Structure of the synaptic junctions in the rat sensorimotor cortex. Freeze-etching study of axodendritic synapses.
The intramembranous structure of axodendritic synapses in the rat sensorimotor cortex was studied by means of freeze-etched replicas and thin sections. In thin sections, symmetric synaptic junctions were located on dendritic shafts. Examination of freeze-etched preparations supported the notion that the postsynaptic dendritic shaft membrane exhibited the same structure as the surrounding non-junctional membrane on both fracture faces. In thin sections, asymmetric perforated and non-perforated synapses were found on dendritic spines and dendritic shafts. In freeze-etched replicas, the postsynaptic membrane of the dendritic spine and some of the dendritic shaft synapses were characterized by perforated and non-perforated aggregates of intramembranous particles at the extracellular half (E-face). These aggregates are accepted as a freeze-etch equivalent of perforated and non-perforated asymmetric synapses seen in thin sections. The intramembranous characteristics of axodendritic synapses in the rat sensorimotor cortex are discussed in terms of synaptic contact zone plasticity.
Bozhilova-Pastirova
A
A
Department of Anatomy and Histology, Medical University, Sofia, Bulgaria.
Ovtscharoff
W
W
D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D003712:Dendrites / Q000648:ultrastructure*; D005613:Freeze Etching; D009044:Motor Cortex / Q000166:cytology*; D009474:Neurons / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000166:cytology*; D013569:Synapses / Q000648:ultrastructure*