The suprahabenular recess in the rat: a quantitative study of ciliated cells, supraependymal cells and some specific features of supraependymal fibres.

Using light microscopy, scanning and transmission electron microscopy, an extensive quantitative analysis of ciliated ependymal cells, supraependymal cells and supraependymal fibres in the suprahabenular recess of twenty-two adult Wistar rats was carried out. In addition, six animals were used to determine the origin of supraependymal fibres and their relationship to ependyma. The findings were as follows: ciliated cells-mean 3.32 +/- 0.26 per 1000 micron 2 (range 0-10); supraependymal cells-5.91 +/- 1.37 per recess (range 2-16). Average number of cilia per cell in different animals ranged from 31 to 33. Sex did not influence the density of ciliated ependyma or supraependymal cells. Evidence was obtained that some supraependymal fibres are closely associated with aberrant commissural fibres. The supraependymal fibres enter the suprahabenular recess and form gap junctions, and other types of junctions, with subjacent ependyma.