Contribution of L-Type Ca2+ Channels to Early Afterdepolarizations Induced by I Kr and I Ks Channel Suppression in Guinea Pig Ventricular Myocytes

Contribution of L-Type Ca2+ Channels to Early Afterdepolarizations Induced by I Kr and I Ks... Early afterdepolizations (EADs) induced by suppression of cardiac delayed rectifier I Kr and/or I Ks channels cause fatal ventricular tachyarrhythmias. In guinea pig ventricular myocytes, partial block of one of the channels with complete block of the other reproducibly induced EADs. Complete block of both I Kr and I Ks channels depolarized the take-off potential and reduced the amplitude of EADs, which in some cases were not clearly separated from the preceding action potentials. A selective L-type Ca2+ (I Ca,L) channel blocker, nifedipine, effectively suppressed EADs at submicromolar concentrations. As examined with the action potential-clamp method, I Ca,L channels mediated inward currents with a spike and dome shape during action potentials. I Ca,L currents decayed mainly due to inactivation in phase 2 and deactivation in phase 3 repolarization. When EADs were induced by complete block of I Kr channels with partial block of I Ks channels, repolarization of the action potential prior to EAD take-off failed to increase I K1 currents and thus failed to completely deactivate I Ca,L channels, which reactivated and mediated inward currents during EADs. When both I Kr and I Ks channels were completely blocked, I Ca,L channels were not deactivated and mediated sustained inward currents until the end of EADs. Under this condition, the recovery and reactivation of I Ca,L channels were absent before EADs. Therefore, an essential mechanism underlying EADs caused by suppression of the delayed rectifiers is the failure to completely deactivate I Ca,L channels. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Contribution of L-Type Ca2+ Channels to Early Afterdepolarizations Induced by I Kr and I Ks Channel Suppression in Guinea Pig Ventricular Myocytes

Loading next page...
 
/lp/springer_journal/contribution-of-l-type-ca2-channels-to-early-afterdepolarizations-U5YNKaNRIB
Publisher
Springer-Verlag
Copyright
Copyright © 2008 by Springer Science+Business Media, LLC
Subject
Life Sciences; Human Physiology ; Biochemistry, general
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-008-9113-9
Publisher site
See Article on Publisher Site

References

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

$49/month

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.

$588

$360/year

billed annually
Start Free Trial

14-day Free Trial