Morphogenesis of synaptic junctions in layers I and II of the somatic sensory cortex
| Autor: | Anthony M. Adinolfi |
|---|---|
| Rok vydání: | 1972 |
| Předmět: |
Vesicle
Morphogenesis Dendrites Somatosensory Cortex Biology Synaptic vesicle Axons Microscopy Electron medicine.anatomical_structure Developmental Neuroscience Neurology Postsynaptic potential Cytoplasm Synapses medicine Ultrastructure Biophysics Cats Animals Synaptic Vesicles Axon Pyramidal cell Neuroscience |
| Zdroj: | Experimental neurology. 34(3) |
| ISSN: | 0014-4886 |
| Popis: | Changes in the ultrastructure of synaptic junctions in layers I and II of developing somatic sensory cortex are described in this study. Dendrites in the molecular layer of newborn kittens are contacted by boutons terminaux and boutons de passage. Presynaptic elements contain very few synaptic vesicles and little or no paramembranous dense material at the contact region. Cleft substance is sparce. A thin plaque of granular material abuts the internal surface of the postsynaptic membrane and produces a slight asymmetry in early axodendritic synapses. During the sixth to tenth postnatal days, symmetrical synaptic junctions develop along pyramidal cell bodies, initial axonal segments and proximal dendrites deep to the molecular layer. Apposing synaptic membranes appear electron dense but lack significant amounts of granular material at their cytoplasmic surfaces. Axodendritic junctions in the molecular layer display prominent postsynaptic densities at this time and are clearly asymmetrical. In addition, asymmetrical axospinous synapses are first observed along apical dendritic shafts. During the third postnatal week, the dendritic spine apparatus develops. Synaptic junctions along proximal cell surfaces in layer II remain symmetrical and synaptic vesicles in many of the deeper-situated axon terminals are flattened, suggesting a late emergence of the ellipsoidal vesicles seen in adult symmetrical synapses. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|