Effects of Chronic Hypoxia on Inward Rectifier K + Current (I K1) in Ventricular Myocytes of Crucian Carp (Carassius carassius) Heart

Effects of Chronic Hypoxia on Inward Rectifier K + Current (I K1) in Ventricular Myocytes of... Some ectothermic vertebrates show unusually good tolerance to oxygen shortage and it is therefore assumed that they might, as a defense mechanism, decrease number or activity of ion channels in order to reduce membrane leakage and thereby ATP-dependent ion pumping in hypoxia. Although several studies have provided indirect evidence in favor of this ‘channel arrest’ hypothesis, only few experiments have examined activity of ion channels directly from animals exposed to chronic hypoxia or anoxia in vivo. Here we compare the inwardly rectifying K+ current (IK1), a major leak and repolarizing K+ pathway of the heart, in cardiac myocytes of normoxic and hypoxic crucian carp, using the whole-cell and cell-attached single-channel patch-clamp methods. Whole-cell conductance of IK1 was 0.5 ± 0.04 nS/pF in normoxic fish and did not change during the 4 weeks hypoxic (O2 < 0.4 mg/l; 2.68 mmHg) period, meanwhile the activity of Na+/K+ATPase decreased 33%. Single-channel conductance of the IK1 was 20.5 ± 0.8 pS in control fish and 21.4 ± 1.1pS in hypoxic fish, and the open probability of the channel was 0.80 ± 0.03 and 0.74 ± 0.04 (P > 0.05) in control and hypoxic fish, respectively. Open and closed times also had identical distributions in normoxic and hypoxic animals. These results suggest that the density and activity of the inward rectifier K+ channel is not modified by chronic hypoxia in ventricular myocytes of the crucian carp heart. It is concluded that instead of channel arrest, the hypoxic fish cardiac myocytes obtain energy savings through ‘action potential arrest’ due to hypoxic bradycardia. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Effects of Chronic Hypoxia on Inward Rectifier K + Current (I K1) in Ventricular Myocytes of Crucian Carp (Carassius carassius) Heart

Loading next page...
Copyright © 2003 by Springer-Verlag New York Inc.
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