Measurement of Evoked Potassium Ion Concentration Dynamics in Coronal Hippocampal Slices

Source: Octeau, J. C. et al. Making, Testing, and Using Potassium Ion Selective Microelectrodes in Tissue Slices of Adult Brain. J. Vis. Exp. (2018). The video demonstrates evoked potassium ion concentration dynamics on electrical stimulation of mouse coronal hippocampal brain slices. A bipolar stimulating electrode is inserted into the stratum radiatum of the CA3 region in the hippocampus, and a potassium-ion selective electrode is placed in the CA1 stratum radiatum. The electrical stimulation causes an action potential, resulting in potassium ion release. Finally, the lack of evoked potassium ion response in the presence of an inhibitory molecule confirms that potassium ion concentration dynamics are due to action potential generation in the Schaffer collaterals.