Why does seal resistance matter for target validation?

Seal resistance above one gigaohm indicates a stable whole-cell configuration, which is essential for reliable ionic current measurements in target validation studies.

How does holding membrane potential at -68 mV support discovery workflows?

Holding the membrane potential at -68 millivolts stabilizes neuronal conditions, enabling consistent measurement of ionic currents across experimental conditions.

What role does capacitance compensation play in assay development?

Compensating for fast and slow pipette capacitance ensures accurate electrical responses, improving data quality in electrophysiological assays.

Why is brief suction applied after pipette retraction?

Applying brief suction through the pipette holder breaks through the cell membrane to establish direct electrical access for whole-cell recording.

Establishing a Whole-Cell Voltage-Clamp Configuration for Electrophysiological Recordings in Brain Slices

Q: How does positive pressure aid in pipette positioning?

Applying slight positive pressure disturbs the tissue surface, indicating proximity to the cell and guiding the pipette toward the target neuron.

JoVE Encyclopedia of Experiments

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0 צפיות • 2:42 דק' • July 8th, 2025

Take a recording pipette with a wire electrode in an electrolyte solution.

Position the pipette above an immobilized brain slice.

Adjust the pipette current to reduce background signals.

Use a microscope to locate the target neuron and move the pipette toward the neuron.

Apply a slight positive pressure and lock it.

The positive pressure disturbs the tissue surface, indicating proximity to the cell.

Bring the pipette closer until a dimple forms on the membrane, signifying correct positioning.

Release the positive pressure.

Observe an increase in resistance as the cell forms a seal with the pipette.

Hold the membrane potential at a constant negative voltage for stability.

Pull the micropipette away to remove excess pressure.

Adjust the pipette's fast and slow electrical responses for accuracy.

Apply brief suction to break through the cell, establishing a direct electrical connection.

The whole-cell voltage clamp configuration is now ready for electrophysiology recording.

To obtain whole-cell configuration, place the recording pipette just above the slice, and offset pipette current in the Voltage Clamp mode. Apply slight positive pressure to the pipette and lock the stopcock.

Next, select a healthy cell with an intact membrane and approach the tissue with the pipette. The positive pressure should cause a slight disturbance on the tissue. Slowly bring the pipette closer to the cell in a diagonal motion until a small dimple is formed on the cell surface. Then, release the positive pressure lock. The cell will begin to form a seal and the resistance will increase above one gigaohm. In voltage clamp, hold the cell at -68 millivolts.

Subsequently, slightly pull the pipette away from the cell diagonally to remove excess pressure. Compensate for the fast and slow pipette capacitance. Apply a brief suction through the tube connected to the pipette holder to break through the cell and obtain a whole-cell configuration.