Light and ultrastructural studies on the ependymal secretion and formation of Reissner's fibre in horses.

The light and electron microscopy was conducted on Reissner's fibre (RF) in 6 young horses of either sex. RF representing cilia, microvilli along with heterogeneous material consisting of RBC and cell debris lay in mid line towards the ventricular surface of the subcommissural organ (SCO) ependyma and cerebral aqueduct. The SEM revealed Reissner's fibre originating from apical spherical protrusions of the SCO. RF of horse presented rough irregular surface due to presence of longitudinal grooves and attachment of RBCs and cell debris. TEM revealed RF as irregular structure cut in different profiles toward the free ventricular surface. Mostly these structures were observed as a single layer. The cytoplasm had smooth and rough endoplasmic reticulum, and a few Golgi complex however, the nucleus and mitochondria were absent.