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Effects of [Ca 2+ ] i and temperature on minK channels expressed in Xenopus oocytes
Author(s) -
Busch Andreas E.,
Lang Florian
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81715-c
Subject(s) - xenopus , mink , chemistry , biophysics , biology , biochemistry , gene , ecology
Slowly activating, voltage‐dependent minK channels cloned from rat kidney were expressed in Xenopus oocytes. Increase in the bath temperature from 22 to 32°C resulted in a dramatic acceleration of minK channel activation. The extraordinarily high Q 10 of minK channel activation was voltage‐dependent, being higher at more negative potentials (Q 10 at −20 mV: 7.02; at 20 mV: 4.0). While activation of minK channels was highly voltage‐dependent at 22°C, voltage had only little effect on minK channel activation at 32°C. Increase in [Ca 2+ ] i , which has recently been shown to increase the maximal conductance g max at room temperature, did not affect g max at 32°C. However, increase of [Ca 2+ ] i caused acceleration of minK channel activation at both temperatures. The interaction of [Ca 2+ ] i and temperature on g max and activation rate of minK channels described here is very similar to recent findings on Ca‐ and temperature‐effects on the slowly activating potassium conductance I Ks in guinea pig cardiac myocytes.