Evidence against an exclusive role of glutamate in kainic acid neurotoxicity

Transection of the non-glutamatergic septohippocampal fibers 3-5 days prior to intrahippocampal microinjection of 1 microgram kainic acid (KA) or 3 micrograms ibotenic acid (IBO) protect dentate granule cells against KA but not IBO. In the transected animals, a significant reduction of KA-induced behavioral seizures can be observed. Neither transection of the hippocampal commissural system nor the fornix contralateral to the intrahippocampal injections protected against KA or IBO neurotoxicity. These findings are discussed in the light of the current hypothesis of KA- and IBO-induced neuronal degeneration.