A transient voltage-dependent outward current in cultured cerebellar granules

• Published in: Bioscience reports Vol. 9; no. 4; p. 451
• Main Authors: Robello, M, Carignani, C, Marchetti, C
• Format: Journal Article
• Language: English
• Published: England 01-08-1989
• Subjects: Animals; Cells, Cultured; Cerebellar Cortex - cytology; Cerebellar Cortex - physiology; Electric Conductivity - physiology; Electric Stimulation; Membrane Potentials; Potassium - physiology; Rats
• ISSN: 0144-8463
• DOI: 10.1007/BF01117047

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.