DECREASED CEREBROSPINAL-FLUID FLOW-THROUGH THE CENTRAL CANAL OF THE SPINAL-CORD OF RATS IMMUNOLOGICALLY DEPRIVED OF REISSNERS FIBER

The subcommissural organ is an ependymal brain gland that secretes gly coproteins to the cerebrospinal fluid (CSF) of the third ventricle. Th ey condense to form a Fibre, Reissner's fibre (RF), that runs along th e aqueduct and fourth ventricle and the central canal of the spinal co rd. A single injection of an antibody against the secretory glycoprote ins of RF into a lateral ventricle of adult rats results in animals pe rmanently deprived of RF in the central canal and bearing a ''short'' RF extending only along the aqueduct and the fourth ventricle. These a nimals, together with untreated control animals were used to investiga te the probable influence of RF in the circulation of CSF in the centr al canal of the spinal cord. For this purpose, two tracers (horseradis h peroxidase and rabbit immunoglobulin) were injected into the ventric ular CSF. The animals were killed 13, 20, 60, 120 and 240 min after th e injection, and the amount of the tracers was estimated in tissue sec tions obtained at proximal, medial and distal levels of the spinal cor d. In rats deprived of RF, a significant decrease in the amount of tra cers present in the central canal was observed at all experimental int ervals, being more evident at 20 min after the injection of the tracer s. 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 th e 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 anima ls.