Editing Electrophysiology (section)

===Patch-clamp recording===
[[File:Patch clamp.svg|thumb|right|The cell-attached [[patch clamp]] uses a micropipette attached to the cell membrane to allow recording from a single ion channel.]]
{{Main|Patch clamp}}
This technique was developed by [[Erwin Neher]] and [[Bert Sakmann]] who received the Nobel Prize in 1991.<ref>{{cite web|url=http://nobelprize.org/nobel_prizes/medicine/laureates/1991/|title=The Nobel Prize in Physiology or Medicine 1991|website=nobelprize.org|access-date=5 May 2018|url-status=live|archive-url=https://web.archive.org/web/20171010211316/https://www.nobelprize.org/nobel_prizes/medicine/laureates/1991/|archive-date=10 October 2017}}</ref> Conventional intracellular recording involves impaling a cell with a fine electrode; patch-clamp recording takes a different approach. A patch-clamp microelectrode is a micropipette with a relatively large tip diameter. The microelectrode is placed next to a cell, and gentle suction is applied through the microelectrode to draw a piece of the cell membrane (the 'patch') into the microelectrode tip; the glass tip forms a high resistance 'seal' with the cell membrane. This configuration is the "cell-attached" mode, and it can be used for studying the activity of the ion channels that are present in the patch of membrane.
If more suction is now applied, the small patch of membrane in the electrode tip can be displaced, leaving the electrode sealed to the rest of the cell. This "whole-cell" mode allows very stable intracellular recording. A disadvantage (compared to conventional intracellular recording with sharp electrodes) is that the intracellular fluid of the cell mixes with the solution inside the recording electrode, and so some important components of the intracellular fluid can be diluted. A variant of this technique, the "perforated patch" technique, tries to minimize these problems.
Instead of applying suction to displace the membrane patch from the electrode tip, it is also possible to make small holes on the patch with pore-forming agents so that large molecules such as proteins can stay inside the cell and ions can pass through the holes freely. Also the patch of membrane can be pulled away from the rest of the cell. This approach enables the membrane properties of the patch to be analyzed pharmacologically.  Patch-clamp may also be combined with RNA sequencing in a technique known as [[Patch-sequencing|patch-seq]] by extracting the cellular contents following recording in order to characterize the electrophysiological properties relationship to gene expression and cell-type.