Changes in extracellular glutamate concentration after acute subdural haematoma in the rat--evidence for an "excitotoxic" mechanism?

Using a rat model of subdural haematoma which is associated with ischaemic damage in the ipsilateral hemisphere, we have measured cerebral blood flow and release of excitatory amino acids after the haematoma. A more than sevenfold rise in glutamate and aspartate, persisting for forty minutes occurred in the severely ischaemic cortex (CBF less than 5 ml 100 gm-1 min-1) and a threefold, sustained rise was seen in hippocampus, although CBF was preserved (85 ml/100 g/-1 min-1). Excitotoxic mechanisms may, therefore, be involved in the ischaemic damage associated with subdural haematoma.