Two-Eletrode Voltage Clamp
Ion Channel Drug Discovery

Two-Electrode Voltage Clamp Assay Services

The Two-Electrode Voltage Clamp (TEVC) is used for assaying channel activity in the Xenopus oocyte expression system. Oocytes from the frog Xenopus laevis have been used extensively in research since the early 1950s. The observation that the eggs can translate exogenous mRNA to express the protein of interest made them a useful tool for to study ion channel activity and how their function can be modified by drug candidates. The TEVC platform allows for evaluation of the activity of compounds against voltage-gated and ligand-gated channels.

  • Ion channels of interest, and mutant forms thereof, can be expressed via mRNA injection into oocytes; thus, there is no need for generation of stable cell lines
  • This is a low throughput platform most suitable for confirming hits from high throughput screens
  • This assay is inexpensive and provides meaningful data in a short turnaround time
  • Single concentration profiling and full concentration-response curves

Assay Principle

Oocytes are injected with mRNA to express the ion channels of interest. The cells get impaled with voltage and current electrodes to control and measure the current passing through the channels expressed on the cell membrane.

Principle of the two-electrode voltage clamp assay performed with xenopus eggs

Principle of the two-electrode voltage clamp assay performed with xenopus eggs

Assay Details

  • Example NMDA receptor
  • Assay Setup
Example NMDA receptor
potentiation of NMDA receptor
Exemplar NMDA receptor subtype 2D (NR2D) trace showing the concentration dependent potentiation of channel activity by a Positive Allosteric Modulator (PAM).
concentration-response curve NMDA
Concentration response curve for the potentiation of NR2D by a PAM
Assay Setup
  • RNA for the channel/receptor of interest is injected into stage V/VI oocytes.
  • Oocytes are incubated at 16 °C; inbubation time 24-72 hours depending on the channel being studied.
  • Channel activity is then assessed using the TEVC.
  • Compounds can be tested at a single concentration or a full curve (6 concentrations).