Role of early edema in the development of regional seizure-related brain damage.

Kainic acid-induced seizures produced early (2 hr) generalized edema and later (24 and 48 hr) necrotic edema in temporal cortex and hippocampus as measured by specific gravity changes. Mannitol given during the seizure partially protected against the early edema and prevented the necrotic edema indicating early edema may play a role in later brain damage. However, H2O intoxication, causing much greater generalized edema than the kainic acid-induced seizures, caused no necrotic edema in temporal cortex or hippocampus at 48 hr. Thus it appears that mannitol protection against kainic acid-induced brain damage may be by a mechanism in addition to dehydration.