BILATERAL INTRANIGRAL NMDA BLOCKADE INCREASES STATUS DURATION AND NEURONAL INJURY FROM SYSTEMIC KAINIC ACID

Limbic seizures may be under the regulation of the substantia nigra, p ars reticulata (SNpr). Using microinjection of the NMDA antagonist AP7 , we investigated the role of SNpr in modulating seizures induced by k ainic acid. Seizure severity was analyzed electrographically and neura l injury assessed by measurement of heat shock protein (HSP) expressio n and acid fuchsin (AF) staining of vulnerable hippocampal cells. Intr anigral injection of AP-7 increased the duration of electrographic sei zure discharges and the number of HSP-positive and acid fuchsin staine d cells in all hippocampal sectors, suggesting that blockade of the NM DA receptors in SNpr enhanced neural injury.