Electron-microscopical study of the choroid plexus and epiplexus cells in XXXX following a cisternal injection of crotoxin complex.

@entity4530 @entity397 @entity36315 @entity35 @entity468
The choroid plexus and its associated epiplexus cells in the fourth ventricle in @entity468 were studied with scanning and transmission electron microscopy (SEM, TEM) following a cisternal injection of @entity36315 complex (phospholipase A2). In SEM, the epiplexus cells of the control animals were predominantly stellate with long radiating processes. At 2 h after the administration of crotoxin complex, these radiating processes flattened out forming sheet-like membranes covering the ventricular surface of the choroid epithelial cells. The membranous coverings remained extended in 5-hour-survival @entity468 . Numerous @entity4530 of different sizes were observed in areas that were not covered by the cytoplasmic membrane in 5-hour animals. Some of the @entity4530 appeared to have @entity397 . In TEM, the microvilli of the choroid epithelial cells in crotoxin complex-treated @entity35 were dilated. The luminal surface of the epithelial cells showed eruption of @entity4530 filled with amorphous materials. Pinocytotic vesicles increased in number in the apical cytoplasm. The lumen of the ventricle often contained portions of cytoplasm believed to be derived from the extrusion of the @entity4530 . These appeared to be engulfed by the overlying epiplexus cells. It was concluded that the injected crotoxin complex stimulated both the secretory as well as pinocytotic activity of the choroid epithelial cells. The phagocytosis of the secretory products from the epithelial cells by epiplexus cells suggests a close functional relationship between the two cell types.
