Changes in the cerebrospinal-fluid monoamines in rats with an immunoneutralization of the subcommissural organ-Reissner's fiber complex by maternal delivery of antibodies

The subcommissural organ (SCO) is a brain gland secreting glycoproteins int o the cerebrospinal fluid (CSF), where they aggregate forming the Reissner' s fiber (RF). By the continuous addition of newly released glycoproteins, R F grows along the cerebral aqueduct, fourth ventricle, and central canal of the spinal cord. At the filum, RF-glycoproteins escape from the central ca nal and reach the local blood vessels. Despite a century of research, the f unction of the SCO remains elusive. The aim of the present investigation wa s to test the hypothesis that RF-glycoproteins, by binding and transporting monoamines out of the CSF, participate in the clearance of these compounds . A protocol was designed that led to the permanent immunoneutralization of the SCO through the maternal delivery of antibodies. This was achieved by transplacental transfer to the fetuses, and through the milk to the pups, o f specific antibodies against SCO secretory proteins. The antibodies reache d the CSF of the fetuses and pups and blocked the RF formation during the f irst months of life. Some of these animals died during the first postnatal weeks; those who survived displayed a rise in the CSF concentration of seve ral monoamines, L-DOPA being the one with the highest rise. Adult rats tran siently deprived of RF by a single injection of anti-RF antibodies into the CSF showed a transient rise in the CSF concentration of L-DOPA. All these results support the hypotheses that the SCO-RF complex participates in the clearance of monoamines from the CSF.