ULTRASTRUCTURAL-LOCALIZATION OF ACETYLCHOLINESTERASE AND CHOLINE-ACETYLTRANSFERASE IN OLIGODENDROCYTES, GLIOBLASTS AND VASCULAR ENDOTHELIAL-CELLS IN THE EXTERNAL CUNEATE NUCLEUS OF THE GERBIL

This study reports the reactivities of acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) in some of the nonneuronal elements in the external cuneate nucleus (ECN) of gerbils. AChE reaction produc ts were localized in some oligodendrocytes in their cisternae of rough endoplasmic reticulum, nuclear envelope and Golgi saccules. The basal lamina lining the capillary endothelia also displayed AChE reactivity . In ChAT immunocytochemistry, the reaction products were found to be associated with the vascular basal lamina as well as the endothelial p lasma membrane facing the lumen. The most remarkable finding was the l ocalization of ChAT immunoreactivity in some oligodendrocytes and occa sional glioblasts (small glial precursor cells containing a thin rim o f cytoplasm surrounding an irregular nucleus with homogeneous chromati n materials). The ChAT-positive oligodendrocytes consisted of two type s, medium-dense and dark cells, either associated with blood vessels o r ChAT-stained neuronal elements. It is suggested from these new findi ngs that at least some of the oligodendrocytes and glioblasts in the E CN of gerbils may be involved in the synthesis, storage, release and d egradation of acetylcholine.