Patchclampteknik

Patchclampteknik is an electrophysiological method used to measure ionic currents through individual ion channels or across small patches of cell membrane. By forming a high-resistance seal between a glass micropipette and the cell membrane, researchers can control the membrane potential and record currents with high fidelity. The technique was developed in the 1970s by Erwin Neher and Bert Sakmann, whose work earned the Nobel Prize in Physiology or Medicine in 1991.

There are four principal configurations. In cell-attached mode, a gigaseal is formed while the cell membrane remains intact, allowing recording of currents through a small patch of membrane. In whole-cell mode, the patch is ruptured to access the cell’s interior and record macroscopic currents. Inside-out mode involves detaching a patch with the intracellular face exposed to the bath, while outside-out mode reconfigures the patch so the extracellular face is exposed to the bath. These configurations enable study of single-channel properties and whole-cell behavior under controlled conditions.

Core equipment includes glass micropipettes with resistances typically in the megaohm range, a micromanipulator, a patch-clamp amplifier, and a Faraday cage with a data-acquisition system. Solutions for the extracellular bath and intracellular milieu are chosen to isolate specific currents. Perforated patch methods use antibiotics to create pores in the patch, allowing electrical access with less disturbance to intracellular constituents.

Applications span neuroscience, cardiology, and pharmacology, including characterization of ion-channel conductance, gating kinetics, drug effects, and channelopathies. Data analysis focuses on current–voltage relationships, single-channel versus macroscopic currents, and corrections such as leak subtraction and series-resistance compensation. Limitations include technical difficulty and low throughput, though variants like perforated patch and dynamic clamp expand capabilities.