O Uso de Fatias de Tecido Cerebral ("Brain Slices") no Estudo da Epilepsia do Lobo Temporal

Abstract

Temporal lobe epilepsy is a common neurological disorder and, perhaps, a window into the nature of neuronal network defects that result in pathological hyperexcitability. Mesial temporal structures play an important and probably predominant role in the causation of complex partial seizures encountered in patients with temporal lobe epilepsy. This evidence has represented the rationale for numerous studies in vivo and in vitro in models of epilepsy in which the main emphasis has been directed toward the physiopathology of the hippocampus proper. Experiments performed in the in vitro hippocampal slice preparation have revealed several fundamental cellular and pharmacological mechanisms responsible for the generation of epileptiform discharges. The brain slice techinique offers the advantages of physical stability, which allows intracellular recording, control over the extracellular ionic medium and pH, and drug aplication. The brain tissue is, of course, isolated from other neural and hormonal inputs, which can be considered an advantage and a disadvantage of the method. Eletrophysiological studies of brain slices have been centered around some main oblectives: 1) descriptions of the cellular biophysical and synaptic properties of neurons, 2) investigations of neurotransmitter function in the brain, that an important issues in determining cellular and synaptic pathologies causing epileptogenesis.