[Correlation between epileptogenic nature of a lesional focus and presence of "activated astrocytes". Human and animal investigation (author's transl)].

Histoenzymologic analysis of human and animal epileptogenic foci has shown enzymatic changes in certain reactive astrocytes. Histochemical examination of these astrocytes in animals has led to clear differentiation between the classic, perilesional reactive astrocyte, constituting a medium for cicatrical glioses and the reactive astrocyte present in experimental epileptogenic foci. We have called the latter the "activated astrocyte". Analysis of 154 human cerebral tumours revealed activated astrocytes in the cortex of all patients with epileptic antecedents. No epileptic attacks were observed in patients where the cortex was invaded by the tumour but no activated astrocytes were present. Analysis of ten cases of non tumoral focal epilepsy confirmed the presence of activated astrocytes in the focus in all cases where the scar was resected surgically. The production of epileptogenic foci in animals shows the close relation between activated astrocytes and the epileptogenic focus. It even seems that the enzymatic changes in the astrocytes precedes the first electrical signs. The authors arguse against the hypothesis that the activated astrocytes are the result of attacks. Until the morphological criteria of the epilectic neuron have been defined the activated astrocyte constitutes the only morphological evidence of the epileptogenic focus.