Zapukhliak O. Epileptiform activity of the rat hippocampus under conditions of complete and partial blockade of synaptic transmission

The dissertation work is devoted to the investigation of the epileptiform activity in the hippocampal rat brain slices under conditions of complete and partial blockade of synaptic transmission. Due to its unique anatomical structure, the hippocampus has a high propensity to reverberate excitation and generate seizure activity. Even during the blockade of synaptic transmission, the hippocampal network is able to generate and maintain synchronized bursting.. The aim of this study was to investigate the characteristics of spontaneous epileptiform activity in CA3–CA1 hippocampus during the complete and partial blockade of synaptic transmission and to determine conditions necessary for its induction. Hippocampal epileptiform activity under conditions of complete and partial blockade of synaptic transmission has distinct patterns. Under low-calcium or cadmium-containing conditions epileptiform activity manifests as fast population spikes, while in presence of AMPA-, NMDA- and GABA-antagonists – it is field discharges. Field discharges – are slow and rhythmic shifts of extracellular potential, which were recorded only during partial blockade with AMPA-, NMDA- and GABA-antagonists, while population spikes were recorded under both complete and partial blockade of synaptic transmission. Level of synchronization of epileptiform activity between CA3 and CA1 zones under nonsynaptic conditions was also compared. Obtained results show that during partial blockade of synaptic transmission level of CA3–CA1-synchronization was higher than under conditions of complete blockade.