HOMOCYSTEIC AND HOMOCYSTEINE SULFINIC ACID EXHIBIT EXCITOTOXICITY IN ORGANOTYPIC CULTURES FROM RAT-BRAIN

The excitotoxic action of homocysteine and related sulphur-containing metabolites was investigated in organotpyic cultures derived from rat brain cortex and hippocampus by inhibition experiments using antagonis ts selective for different glutamate receptor subtypes. In addition th e direct interaction of these metabolites with glutamate receptors exp ressed in frog oocytes was tested by conventional two electrode voltag e clamp techniques. Conclusion Neurodegeneration and epilepsy observed in homocystinuria may be mediated by L-homocysteic and L-homocysteine sulphinic acid. Both metabolites exhibit exci totoxic potency by inte raction with different glutamate receptor subtypes.