A unique feature of Nanion’s automated patch clamp platforms is the possibility to exchange intracellular components. With conventional patch clamp this is difficult because of the tiny dimensions of the pipette tip, the long tapered shaft and, thus, the diffusion limitation of the liquid exchange. With Nanion’s systems ion channels regulated by second messengers acting on internal binding sites can be modulated simultaneously by compound additions to the external side of the membrane. This allows for novel and complex experiments on interactions between ion channels and drugs. Another aspect of internal perfusion is the possibility to add membrane permeable drugs directly to the inside of the cell and, thereby, accelerating the time course of the experiment.

Manual internal solution exchange. Using the Port-a-Patch, the internal solution can be exchanged using a pipette. As an example, pore forming compounds like Nystatin can be used to perforate the membrane patch in order to obtain electrical control over the membrane. Thus the cell´s interior remains intact and the cytosolic constituents that can be important for ion channel function are preserved.

Perforated and conventional whole cell configuration and derived K_v1.3-currents. K_v1.3 has been described as to show a shift of its voltage dependence to more positive potentials when recorded in the perforated whole cell configuration. In our recordings performed with the Port-a-Patch we could confirm this observation. The voltage-dependence was shifted significantly to more negative potentials in the whole cell configuration compared to the perforated whole cell configuration. Whole cell currents after a conventional membrane breakthrough (left) and perforated whole cell currents (middle). Nystatin was added to the internal solution after the cell attached configuration was reached. I-V curves of peak current of 3 (conventional) and 5 (perforated) cells (right).