Synaptophysin Expression by Supraependymal Structures of the Rat Brain

Supraependymal plexus in ventricular system is one of the most cryptic structures in the mammalian central nervous system. Since both the topography of supraependymal elements and their functional role remain unclear, the aim of this research was to study the distribution of supraependymal structures within the ventricular system of the rat brain with synaptic function associated marker, synaptophysin. Serial sections of Wistar rats (4–6 month, n = 6) forebrain were examined using immunohistochemical detection of synaptophysin and tyrosine hydroxylase. It was shown that supraependymal plexus can form on the surface of ependymal cells synaptophysin-immunopostitive discrete structures, which indicates the formation of synaptic contacts. Although catecholaminergic nerve fibers were present on the ventricular surface in all studied zones, it seems that these nerve fibers may not always contain synaptophysin. Thus, it is assumed that the functional purpose of the supraependymal nerve plexus depends on its localization and can be associated whether with the regulation of ependymal cells and cerebrospinal fluid formation, or with the formation of long-range interneuronal connectivities.