Journalartikel

Jahr der Veröffentlichung: 1994

Seiten: 79-87

Zeitschrift: Biochimica et Biophysica Acta (BBA) - Biomembranes

Bandnummer: 1192

Heftnummer: 1

ISSN: 0005-2736

DOI Link: https://doi.org/10.1016/0005-2736(94)90145-7

Verlag: Elsevier

Abstract: 
Voltage- and Ca2+-dependence of the slow-activating SV-K+ channel in the vacuolar membrane of Chenopodium rubrum suspension cells has been analyzed using the patch clamp technique in the vacuole-attached, outside-out and whole-vacuolar configuration. Patch-pipette perfusion was applied to measure Ca2+ dependence of single channels in the attached-configuration. Using the PCLAMP-software (Axon Instruments), an algorithm was developed to extract reliable individual channel data from multi-channel activity records, including open probability, mean open and closed times, as well as time constants for open and closed distributions. The channel conductance of the major open state was about 83 pS (seal resistance > 8 G Omega) at 30 mV (transmembrane voltage V-m, vacuole negative), and symmetrical 100 mM KCl. The channel exhibited a strong voltage- and a weak Ca2+-activation: increasing V, from 40 to 100 mV is equivalent to a Ca2+ concentration change from 10(-7) to 10(-4) M. Mean open probabilities at V-m = 30 mV were 0.03 with 1 mu M and 0.09 with 100 mu M Ca2+. Mean open times were approx. 7 ms. and almost independent of both, voltage and Ca2+. Mean closed times, however, varied in a strongly voltage- and Ca2+-dependent manner, e.g., at V-m = 30 mV dropped from 205 to 67 ms, if Ca2+ was raised from 10(-6) to 10(-4) M. Open and closed distributions of events within bursts could be fitted by the sum of two exponentials with time constants between 0.3 and 11 ms.

Harvard-Zitierstil: REIFARTH, F., WEISER, T. and BENTRUP, F. (1994) VOLTAGE-DEPENDENT AND CA2+-DEPENDENT OF THE K+ CHANNEL IN THE VACUOLAR MEMBRANE OF CHENOPODIUM-RUBRUM L SUSPENSION CELLS, Biochimica et Biophysica Acta (BBA) - Biomembranes, 1192(1), pp. 79-87. https://doi.org/10.1016/0005-2736(94)90145-7

APA-Zitierstil: REIFARTH, F., WEISER, T., & BENTRUP, F. (1994). VOLTAGE-DEPENDENT AND CA2+-DEPENDENT OF THE K+ CHANNEL IN THE VACUOLAR MEMBRANE OF CHENOPODIUM-RUBRUM L SUSPENSION CELLS. Biochimica et Biophysica Acta (BBA) - Biomembranes. 1192(1), 79-87. https://doi.org/10.1016/0005-2736(94)90145-7