voltageclampmethoden

Voltage clamp methods, often written as voltage clamp methods or voltageclampmethoden in German contexts, are electrophysiological techniques used to control the membrane potential of a cell while measuring ionic currents across the membrane.

The core idea is to clamp the membrane at a chosen command potential using a feedback amplifier. The amplifier injects current through an intracellular or extracellular electrode to counteract the cell's passive and active currents. The current required to hold the potential is recorded and reflects the net ionic current. The method differs from current clamp, which records voltage while injecting current to observe endogenous voltage changes.

Common implementations include the two-electrode voltage clamp (TEVC) used in large cells such as Xenopus oocytes and muscle fibers, and the patch-clamp voltage clamp, including whole-cell and perforated-patch configurations for mammalian cells. Protocols include voltage steps, ramps, and tail-current measurements to probe ion channel kinetics and conductance–voltage relationships.

Applications include studying voltage-gated Na+, K+, Ca2+ channels, receptor-operated channels in neurons, cardiac myocytes, pharmacology of channel blockers, and ion channelopathies. Limitations include imperfect space clamp in neurons with complex morphologies, series resistance and leak currents, electrode drift, and the need for rigorous calibration and compensation.