Glial cells of the central nervous system in the crab Ucides cordatus

Glial cells and their processes were characterized in the fasciculated zone and in the protocerebral tract of the crab Ucides cordatus by light and el ectron microscopy. Thiery and PAS procedures indicate the presence of carbo hydrates, particularly glycogen in cells. Immunohistochemistry was used to observe tubulin distribution in the glial cells. Our results demonstrate at least two types of glial cells in the fasciculated zone and in the protoce rebral tract, separable by their location and electron density. Judging by their position, electron-lucent cells may correspond to periaxonal cells an d electron-dense ones may correspond to perineurial cells. The electron-den se processes have previously been interpreted as extracellular matrix, but since they feature an enveloping membrane and contain glycogen and mitochon dria (intact and with varying degrees of disruption) we consider them to be part of one type of glial cells.