Neuropathological alterations in the neocortex of rats subjected to focal aminopyridine seizures.

Acute focal seizures were produced in anaesthetized albino rats by topical application of 3- and 4-aminopyridine on the exposed fronto-parietal neocortical areas. After 15 min of seizure activity neuronal and glial changes were studied by light (toluidine blue and Golgi staining) and electron microscopy. Shrinkage and increased electron density of some pyramidal cells, astrocytic swelling and depletion of 40-60 nm synaptic vesicles from the nerve terminals in layers I, II and III were found. The possible significance of the alterations in the seizure is discussed.