A transient voltage-dependent outward current in cultured cerebellar granules.
Granule cells were dissociated from rat cerebella with a procedure that yields a 98% pure cell population. Potassium currents in these cells were studied using the patch-clamp technique. Depolarizing pulses of 10 mV step and 100 ms duration from a holding potential of -80 mV elicited two different potassium outward currents: a transient, low-voltage activated component and a long lasting, high-voltage activated component. At +30 mV, the total current reached an amplitude of 2 nA (mean value of 15 experiments). The reversal potential of the transient current, estimated by measuring tail currents, was -77 mV, close to that predicted by the Nernst equation. The transient current was half inactivated with a holding potential of -78 mV and completely inactivated with -50 mV or more positive holding potentials. Finally, the current decay could be fitted by the sum of two exponentials with time constants of about 20 and 250 ms.
Robello
M
M
Dipartimento di Fisica, Universita' di Genova, Italy.
Carignani
C
C
Marchetti
C
C
D000818:Animals; D002478:Cells, Cultured; D002525:Cerebellar Cortex / Q000166:cytology / Q000502:physiology*; D004553:Electric Conductivity / Q000502:physiology; D004558:Electric Stimulation; D008564:Membrane Potentials; D011188:Potassium / Q000502:physiology*; D051381:Rats
D011188:Potassium