[Pathophysiology of epilepsy].
Epilepsy is a paroxysmally occurring disturbance of brain function. The neurones directly involved in the epileptic process show characteristic behaviour of the membrane potential, which consists of a rectangular-shaped depolarization recorded in neurones during all experimental models of epilepsy investigated up to now. Occasional recordings in patients have shown a similar reaction of the membrane potential. The membrane potential fluctuation is therefore regarded as the specific reaction of a neurone directly involved in the epileptic process, and the accordingly termed "paroxysmal depolarization shift" (PDS) was found to be the expression of pathophysiologic behaviour by the neuronal membrane. The "epileptic" neurones are hemispherically surrounded by neurones which are simultaneously inhibited. The mechanisms capable of overcoming the surrounding inhibition and thus leading to the spread of epileptic activity are not fully understood as yet: seizure-related changes in the extracellular ionic environment appear to support the spreading process. The termination of an epileptic event is not necessarily the result of metabolic exhaustion of the nerve cells involved. Recent data indicate a prominent role for primary neuronal mechanisms in the termination of a seizure. However, the cortical tissue participating in a partial seizure shows increased vulnerability to hypoxia. Brain damage found in central nervous tissue of epileptics may therefore be the result of secondary cerebral hypoxia consequent on seizure-related disturbances of breathing and circulation.
D000818:Animals; D001921:Brain / Q000503:physiopathology; D002415:Cats; D004569:Electroencephalography; D004827:Epilepsy / Q000503:physiopathology*; D006801:Humans; D008564:Membrane Potentials; D010313:Partial Pressure; D051381:Rats
Pathophysiologie der Epilepsie.