Kv1.3 is a voltage-gated potassium channel with roles in human T cell activation/ proliferation, cell-mediated cytotoxicity, and volume regulation and is thus a target for therapeutic control of T cell responses.
The channel activity is induced upon membrane depolarization to voltages more positive than –40 mV. Activation kinetics are rapid and strongly voltage-dependent, whereas inactivation is much slower and shows no significant voltage dependence.

Reproducibility. The top left figure shows simultaneously recorded currents of two Jurkat cells. The application of 5 μM Quinidine leads to a partial block (red line) of the Kv1.3 currents (top right, only one cell shown). After a washing step the current is fully recovered (grey line). The lower figure shows the corresponding I max (+40 mV) in the presence of the control solution or 5 μM Quinidine of both cells (8 consecutive application- and washout- steps).

Internal solution exchange. A unique feature of the Patchliner is the internal solution exchange between two recordings. The figure shows two simultaneously recorded Jurkat cells in the presence of a control internal solution, after the exchange of the internal solution with a Cs+ containing solution and a subsequent washout step. The ability to change the internal solution several times, along with long lasting and stable whole cell recordings possible with the Patchliner, opens up a broad new range of experiments.