[Audiogenic epilepsy: a morphofunctional analysis]

Abstract

The rats of K-M line with high level of convulsive readiness to sound stimuli were tested. It was established that systemic application of epileptogenic stimulus evoked the decrease of level of convulsive readiness. The phenomena of habituation and normalization of animal behavior were revealed. The intraperitoneal injection of inhibitory transmitter--GABA and taurine (separately or in mixture) blocked the convulsive seizures. The functional influence by KCl-induced spreading depression in the cerebral cortex bilaterally impairs the inhibitory processes, but not the changes the form of epileptiform seizure. In neurophysiological experiments using microelectrophoresis technique it was shown that taurine as inhibitory agent is more effective when applied to dendritic layers II-III; GABA is more effective if it is applied on soma of cortical pyramidal cells. Using the electron microscopic methods, the following changes were observed during the clonic seizure: axo-dendritic and axo-spine synapses in rat auditory cortex were activated. After the habituation to the epileptogenic stimulus, some features evidencing the decrease of activity were observed in ultrastructure of synapses in layers II-III. In 2 days after that the majority of ultrastructural shifts were normalized. Role of calcium ions in generation of epileptic seizures and their depression as main factor of antiepileptic mechanisms is discussed.