Regensburg 2004 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.73: Poster

Freitag, 12. März 2004, 10:30–13:00, B

Fast and Slow Transistor Records of Recombinant Voltage-Gated K⁺ Channels — •Matthias Brittinger and Peter Fromherz — MPI für Biochemie, Abt. Membran und Neurophysik, Martinsried

To understand transistor recording of neuronal excitation it is necessary to study the response to defined voltage-gated ion channels under voltage-clamp.

HEK 293 cells were stable transfected with Kv1.3 potassium channels and cultured on field effect transistors with an exposed silica gate. We observed two kinds of transistor signals on a time scale of one microsecond and ten milliseconds when the Kv1.3 channels opened and closed. The relative amplitudes depended on the extracellular concentrations of sodium and potassium.

The fast signal is due to a change of the gate voltage as caused by charge diffusion in a core-coat conductor. The slow signal is related with a change of extracellular ion concentration (electrodiffusion) which affects the transistor threshold. It is rationalized in all details by a Stern model of the electrical double layer with binding dynamics of potassium ions.