The surface fine structure of the choroid plexus and ependymal lining of the rat lateral ventricle.

Abstract

The surfaces of cells of the ependyma and choroid plexus in the lateral ventricle of the mature rat brain have been examined with a scanning electron microscope on tissue dried by the critical point method. The ventricular surfaces of the choroid plexus cells are domed and have a tangle of thin processes resembling microvilli. The cilia possessed by these cells could not be identified. Overlying the choroid plexus are a number of free cells. These cells have many fine processes extending from them. They are probably macrophages and have been equated with the Kolmer or epiplexus cells which are known to rest on the surface of the choroidal epithelium.