In Vivo Real-Time Glutamate Monitoring Using an Enzyme-Coated Microelectrode Array

Begin with an anesthetized mouse secured on a stereotaxic frame, with the skull exposed.

Identify the skull reference points, and then mark the target coordinates.

Drill around the mark, remove the bone flap to expose the brain tissue, and clean the surface.

Attach a multielectrode array or MEA coated with glutamate oxidase enzyme and a micropipette to the stereotaxic frame.

Place the reference electrode away from the MEA while maintaining liquid contact with the brain to complete the circuit.

Fill the micropipette with a glutamate solution.

Now, Lower the MEA and micropipette into the brain tissue rich in neurons and astrocytes. Record the baseline electrical signal from the MEA.

Inject the glutamate solution to rapidly increase the glutamate levels in the extracellular space containing the MEA.

The glutamate oxidase on the MEA oxidizes the glutamate, generating an electrical signal.

As astrocytes uptake glutamate, extracellular glutamate levels decrease, reducing the signal and allowing for real-time glutamate monitoring.