Differential Regulation of Calcium-Activated Potassium Channels by Dynamic Intracellular Calcium Signals

Differential Regulation of Calcium-Activated Potassium Channels by Dynamic Intracellular Calcium... Calcium (Ca2+)-activated K+ (KCa) channels regulate membrane excitability and are activated by an increase in cytosolic Ca2+ concentration ([Ca2+]i), leading to membrane hyperpolarization. Most patch clamp experiments that measure KCa currents use steady-state [Ca2+] buffered within the patch pipette. However, when cells are stimulated physiologically, [Ca2+]i changes dynamically, for example during [Ca2+]i oscillations. Therefore, the aim of the present study was to examine the effect of dynamic changes in [Ca2+]i on small (SK3), intermediate (hIK1), and large conductance (BK) channels. HEK293 cells stably expressing each KCa subtype in isolation were used to simultaneously measure agonist-evoked [Ca2+]i signals, using indo-1 fluorescence, and current/voltage, using perforated patch clamp. Agonist-evoked [Ca2+]i oscillations induced a corresponding KCa current that faithfully followed the [Ca2+]i in 13–50% of cells, suggesting a good synchronization. However, [Ca2+]i and KCa current was much less synchronized in 50–76% of cells that exhibited Ca2+-independent current events (55% of SK3-, 50% of hIK1-, and 53% of BK-expressing cells) and current-independent [Ca2+]i events (18% SK3- and 33% of BK-expressing cells). Moreover, in BK-expressing cells, where [Ca2+]i and KCa current was least synchronized, 36% of total [Ca2+]i spikes occurred without activating a corresponding KCa current spike, suggesting that BKCa channels were either inhibited or had become desensitized. This desynchronization between dynamic [Ca2+]i and KCa current suggests that this relationship is more complex than could be predicted from steady-state [Ca2+]i and KCa current. These phenomena may be important for encoding stimulus–response coupling in various cell types. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Differential Regulation of Calcium-Activated Potassium Channels by Dynamic Intracellular Calcium Signals

Loading next page...
Copyright © 2010 by Springer Science+Business Media, LLC
Life Sciences; Human Physiology ; Biochemistry, general
Publisher site
See Article on Publisher Site


You’re reading a free preview. Subscribe to read the entire article.

DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches


Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.



billed annually
Start Free Trial

14-day Free Trial