Measurement of Evoked Potassium Ion Concentration Dynamics in Coronal Hippocampal Slices
Transcription
Secure a mouse coronal brain slice in a recording chamber filled with aCSF.
Insert a bipolar stimulating electrode into the stratum radiatum of the CA3 region in the hippocampus. The CA3 neurons project their axons, termed Schaffer collaterals, to CA1.
Position a potassium ion-selective electrode in the CA1 stratum radiatum.
Electrically stimulate CA3 neurons to open voltage-gated sodium channels. The sodium ion influx turns the membrane potential positive, termed depolarization, and generates an action potential.
After the peak of depolarization, sodium channels deactivate, and voltage-gated potassium channels allow potassium ion outflow, repolarizing the membrane. Subsequently, the membrane potential is restored, and the action potential propagates to CA1.
The potassium ion-selective electrode measures the outflow, shown by a response curve.
Add a blocker to inhibit voltage-gated sodium channel activity. Upon electrical stimulation, a lack of potassium ion response confirms that its dynamics are due to action potentials in the Schaffer collaterals.
