[Activated astrocytes and epileptogenic focus. Histoenzymology]

Abstract

The author reports the discovery of an original entity, the activated astrocyte, which is an essential component and the first anatomical sign of the epileptogenic focus. The importance of the activated astrocyte is demonstrated by the fact that it is observed before the clinical signs appear and as soon as the first spikes are recorded on the electrocortigram. Cautious conclusions are drawn. The authors recognizes the essential role of the neurons and does not suggest that astrocytes are the cause of epilepsy. However, since astrocyte activation is observed before the first electrical signs announce the beginning of an epileptogenic focus, he suggests that activated astrocytes probably offer morphological evidence of certain mechanisms closely concerned in the formation of the epileptogenic focus. The metabolic activation of the astrocyte is not surprising, and is probably related to the increase in loco-regional metabolism due to neuronal hyperactivity, the starting point of epilepsy. It confirms current opinion, especially in biochemistry, on the importance of the glial cells in the neuronastrocyte association. This work opens up certain prospects. First, the significance of the activated astrocyte in the context of current biochemical, neuro-physiological and morphological studies of the glial compartment is a promising research field. Second, from the clinical angle, it is very important to be able to identify an epileptogenic gliosis on the basis of activated astrocytes. Used in conjunction with modern neuro-physiological techniques to locate the epileptogenic focus, the search for activated astrocytes in biopsy material obtained stereotactically should permit better detection of the affected area and thus ensure more successful surgery in cases of focal epilepsy resistant to medication.