Chronic aluminum intoxication in rat induced both serotonin changes in the dorsal raphe nucleus and alteration of glycoprotein secretion in the subcommissural organ: Immunohistochemical study

Abstract

Aluminum (Al) causes multiple impairments in several body systems including the central nervous system. In fact, Al exposure has been mostly associated with neurological dysfunctions that occur in some brain diseases. The effect of Al neurotoxicity on the dopaminergic system is well documented, but this effect on the serotoninergic system is poorly studied. The aim of this work is to evaluate the effect of chronic Al intoxication (0.3% of aluminum chloride exposure from the intra-uterine age until 4 months of adult age) on dorsal raphe nucleus (DRN) which is the main source of serotonin, and also on the glycoprotein secretion of subcomissural organ (SCO), receiving important serotoninergic innervation. This will be executed using immunohistochemistry procedure, with both the anti serotonin and the anti Reissner's fiber antibodies in the rat. Our results showed a significant increase of serotonin immunoreactivity in the DRN, accompanied by a noticeable decrease of RF immunoreactivity in the SCO ependymocytes. This study provides further evidence confirming the toxic effect of Al exposure on serotonin neurotransmission in the brain likely through increased synthesis or decreased release. Al exposure was also shown to decrease RF glycoprotein which is involved in the detoxification of cerebrospinal fluid.