Electron microscopy of glial cells of the central nervous system in the crab Ucides cordatus

Invertebrate glial cells show a variety of morphologies depending on words species and location. They have been classified according to relatively Gli al cells general morphological or functional criteria and also to their loc ation. Crustacea The present study was carried out to characterize the orga nization of glial cells and their processes in the zona fasciculata and in the protocerebral tract of the crab Ucides cordatus. We performed routine a nd cytochemical procedures for electron microscopy analysis. Semithin secti ons were observed at the light microscope. The Thiery procedure indicated t he presence of carbohydrates, particularly glycogen, in tissue and in cells . To better visualize the axonal ensheathment at the ultrastructural level, we employed a method to enhance the unsaturated fatty acids present in mem branes. Our results showed that there are at least two types of glial cells in these nervous structures, a light one and a dark one. Most of the dark cell processes have been mentioned in the literature as extracellular matri x, but since they presented an enveloping membrane, glycogen and mitochondr ia intact and with different degrees of disruption - they were considered t o be glial cells in the present study. We assume that they correspond to th e perineurial cells on the basis of their location. The light cells must co rrespond to the periaxonal cells. Some characteristics of the axons such as their organization, ensheathment and subcellular structures are also descr ibed.