Decreased cerebrospinal fluid flow through the central canal of the spinal cord of rats immunologically deprived of Reissner's fibre

Abstract

The subcommissural organ is an ependymal brain gland that secretes glycoproteins to the cerebrospinal fluid (CSF) of the third ventricle. They condense to form a fibre, Reissner's fibre (RF), that runs along the aqueduct and fourth ventricle and the central canal of the spinal cord. A single injection of an antibody against the secretory glycoproteins of RF into a lateral ventricle of adult rats results in animals permanently deprived of RF in the central canal and bearing a "short" RF extending only along the aqueduct and the fourth ventricle. These animals, together with untreated control animals were used to investigate the probable influence of RF in the circulation of CSF in the central canal of the spinal cord. For this purpose, two tracers, (horseradish peroxidase and rabbit immunoglobulin) were injected into the ventricular CSF. The animals were killed 13, 20, 60, 120 and 240 min after the injection, and the amount of the tracers was estimated in tissue sections obtained at proximal, medial and distal levels of the spinal cord. In rats deprived of RF, a significant decrease in the amount of tracers present in the central canal was observed at all experimental intervals, being more evident at 20 min after the injection of the tracers. This suggests that lacking a RF in the central canal decreases the bulk flow of CSF along the central canal. Turbulences of the CSF at the entrance of the central canal of RF-deprived rats might explain the inability of the regenerating RF to progress along the central canal, as well as the reduced flow of CSF in the central canal of these animals.

The subcommissural organ

“…A single injection of these antibodies leads to an immediate disruption of RF and to the formation of a new RF several days later (S. Rodríguez et al, 1990). These immunologically RF-deprived rats show a disturbance in the urine flow and water intake (S. and to severe alterations in the circulation of the CSF in the central canal (Cifuentes et al, 1994;Fernán-dez-Llebrez et al, 1993).…”

Functional aspects of the subcommissural organ-Reissner's fiber complex with emphasis in the clearance of brain monoamines

“…Eight days later, these rats show a new RF reaching the fourth ventricle but it never reenters into the central canal of the spinal cord. This method blocks in a transient form the formation of the RF (Cifuentes et al, 1994;S. Rodríguez et al, 1990).…”

Graded phenotypic response to partial and complete deficiency of a brain-specific transcript variant of the winged helix transcription factor RFX4

“…Anatomical characterization of these mice revealed severe congenital hydrocephalus that was nonetheless compatible with life and fertility in some cases. This obstructive hydrocephalus appeared to be secondary to failure of development of the subcommissural organ (SCO), a structure that is important for the patency of the aqueduct of Sylvius and normal cerebrospinal fluid flow in the brain (Cifuentes et al, 1994;Perez-Figares et al, 1998;PerezFigares et al, 2001;Rodriguez et al, 2001;Rodriguez et al, 1998;Vio et al, 2000). Identification of the genomic sequences flanking the inserted transgene led to the discovery that the transgene interfered with the expression of a novel brainspecific isoform of the winged helix transcription factor regulatory factor X4 (RFX4), which has been named RFX4 variant transcript 3, or RFX4_v3.…”