Electroporation-Induced Inward Current in Voltage-Clamped Guinea Pig Ventricular Myocytes

Electroporation-Induced Inward Current in Voltage-Clamped Guinea Pig Ventricular Myocytes Electroporation induced by high-strength electrical fields has long been used to investigate membrane properties and facilitate transmembrane delivery of molecules and genes for research and clinical purposes. In the heart, electric field-induced passage of ions through electropores is a factor in defibrillation and postshock dysfunction. Voltage-clamp pulses can also induce electroporation, as exemplified by findings in earlier studies on rabbit ventricular myocytes: Long hyperpolarizations to ≤−110 mV induced influx of marker ethidium and irregular inward currents that were as large with external NMDG+ as Na+. In the present study, guinea pig ventricular myocytes were bathed with NMDG+, Na+ or NMDG+ + La3+ solution (36°C) and treated with five channel blockers. Hyperpolarization of myocytes in NMDG+ solution elicited an irregular inward current (I ep) that reversed at −21.5 ± 1.5 mV. In myocytes hyperpolarized with 200-ms steps every 30 s, I ep occurred in “episodes” that lasted for one to four steps. Boltzmann fits to data on the incidence of I ep per experiment indicate 50% incidence at −129.7 ± 1.4 mV (Na+) and −146.3 ± 1.6 mV (NMDG+) (slopes ≈−7.5 mV). I ep amplitude increased with negative voltage and was larger with Na+ than NMDG+ (e.g., −2.83 ± 0.34 vs. −1.40 ± 0.22 nA at −190 mV). La3+ (0.2 mM) shortened episodes, shifted 50% incidence by −35 mV and decreased amplitude, suggesting that it inhibits opening/promotes closing of electropores. We compare our findings with earlier ones, especially in regard to electropore selectivity. In the Appendix, relative permeabilities and modified excluded-area theory are used to derive estimates of electropore diameters consistent with reversal potential −21.5 mV. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Electroporation-Induced Inward Current in Voltage-Clamped Guinea Pig Ventricular Myocytes

Loading next page...
 
/lp/springer_journal/electroporation-induced-inward-current-in-voltage-clamped-guinea-pig-Rk0UCbOTf5
Publisher
Springer-Verlag
Copyright
Copyright © 2010 by Springer Science+Business Media, LLC
Subject
Life Sciences; Human Physiology ; Biochemistry, general
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-010-9320-z
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