[Morpho-functional characterictic of rat lumbar spinal cord enlargement].

Topography and the distribution of synaptophysin-immunoreactive structures were studied in the rat lumbar spinal cord enlargement. Synaptophysin (synaptic vesicle marker) was found in the gray matter of all Rexed laminae around most neurons and in neuropil. Subpial synaptic contacts, that were not described previously, were found in the white matter by immunohistochemistry and their presence was confirmed by electron microscopy. They were localized directly beneath the astrocyte processes, that cover the spinal cord externally. In the dorsal portion of the white matter within the lumbar spinal cord enlargement, the unmyelinated synaptophysin-immunoreactive component of pyramidal tract was detected which included axonal varicosities and synaptic contacts.