UNUSUAL NEOCORTICAL PRESYNAPTIC TERMINALS IN A PATIENT WITH CONVULSIONScomma; MENTAL RETARDATION AND CORTICAL BLINDNESSAN ELECTRON MICROSCOPIC STUDY

摘要

1. Large presynaptie axon terminals in axodendritic and probably in axo-somatic synapses have been noted with the electron microscope in the frontal cortex of a 21/2 year old girl suffering from generalized convulsions, myoclonus, mental retardation, and cortical blindness.2. The enlarged axon terminals were 5 to 10 times the normal sire and measured 2.5 to 5 micra in diameter. They contained fibrils, 100 to 150 Aring; in thickness, tubules 200 Aring; in thickness, vesicular-like branching membranous profiles, synaptic vesicles, and occasional mitochondria.3. The intersynaptic clefts and postsynaptic processes and neuronal peri-karya appeared normal.4. In tissue, fixed in glutaraldehyde prior to osmium fixation, fusions of plasma membranes of normal and enlarged axon terminals with adjacent glial cells, axous or neuronal perikarya were constantly noted: the inter-synaptic clefts were not fused. The fusions, probably reflect the effect of this mode of fixation and are not related to pathologic changes, as they were not observed in specimens fixed in osmium alone.5. The relationships between the ultrastructural findings and clinical symptomatology have been discussed and the possible role of the changes in the presynaptic axonal ending in the synaptic dysfunction has been suggested.