Patch-clamp

Patch-clamp is a laboratory technique in Electrophysiology used to study ionic currents in individual isolated living cells, tissue sections, or patches of cell membrane. The technique is especially prominent in the study of neurons and cardiomyocytes, although it can be applied to any kind of electrically active cell.

History

The patch-clamp technique was developed by Erwin Neher and Bert Sakmann in the late 1970s. The two scientists were awarded the Nobel Prize in Physiology or Medicine in 1991 for their work.

Technique

The patch-clamp technique involves the use of a glass pipette, which is brought into contact with a cell membrane. A vacuum is applied to the pipette, causing a piece of the cell membrane to adhere to the pipette tip, forming a 'patch'. The ionic currents through the membrane patch can then be measured.

There are several variations of the patch-clamp technique, including:

• Cell-attached patch - The pipette is attached to the cell membrane, but does not break it. This allows for the study of the activity of individual ion channels within the patch.
• Whole-cell patch - The pipette breaks the cell membrane, allowing for the study of the cell's overall electrical activity.
• Inside-out patch - The pipette is pulled away from the cell after forming a cell-attached patch, bringing a piece of the cell membrane with it. This allows for the study of the intracellular side of the membrane.
• Outside-out patch - After forming a whole-cell patch, the pipette is pulled away from the cell, causing the membrane to reseal itself around the pipette tip. This allows for the study of the extracellular side of the membrane.

Applications

Patch-clamp is widely used in the study of neuroscience, cardiology, and pharmacology. It allows for the detailed study of ion channels, which are crucial for the electrical activity of cells. This has led to important discoveries in the understanding of diseases such as cystic fibrosis, epilepsy, and various cardiac arrhythmias.

See also

• Voltage clamp
• Current clamp
• Electrophysiology