Focal potassium microinjection in rat hippocampal slices inducing interictal activities

Focal potassium microinjection induces the incidence of epileptiform activities of rat hippocampal slices. We investigated the seizure responses of this activity in vitro using extracellular records from acute rat hippocampal slice. The electrophysiological recordings were performed on CA3 regions during microinjection of high potassium chloride. High potassium (8.5 mM) induces interictal field potentials generated spontaneously in the injected region of CA3. High-frequency bursting analogous to ictal seizure activity was locally obtained in the slice regarding to changes in cellular excitability synaptic signaling of potassium channel which may contribute to this phenomenon equivalent to the potassium bathed method. This study concludes that the focal potassium microinjection significantly initiates seizure at CA3 region and is a suitable model for investigating focal epileptogenesis in hippocampal slice.