Two Electrode Voltage Clamp of Oocytes
The voltage clamp technique is a method that allows ion flow across the cell membrane to be measured as an electric current as the transmembrane potential is held under constant experimental control with a feedback amplifier. Ion channels expressed in Xenopus oocytes can be studied using the two-microelectrode voltage clamp. The membrane of the oocyte is penetrated by two microelectrodes, one for voltage sensing and one for current injection. The membrane potential as measured by the voltage-sensing electrode and a high input impedance amplifier is compared with a command voltage, and the difference is brought to zero by a high gain feedback amplifier. The injected current is monitored via a current-to voltage converter to provide a measure of the total membrane current.
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