ATP-sensitive potassium channels (K ATP ) in retina: a key role for delayed ischemic tolerance

ATP-sensitive potassium channels (K ATP ) in retina: a key role for delayed ischemic tolerance The objectives of the present study were to determine the localization of K ATP channels in normal retina and to evaluate their potential roles in ischemic preconditioning (IPC) in a rat model of ischemia induced by increased intraocular pressure (IOP). Brown Norway rats were subjected to sublethal 3-, lethal 20- and 40-min ischemia and the functional recovery was evaluated using electroretinography. The time interval between ischemic insults ranged from 1 to 72 h. The effects of K ATP channel blockade on IPC protection were studied by treatment with 0.01% glipizide. IPC was mimicked by injection of K ATP channel openers of 0.01% (−)cromakalim or 0.01% P1060 72 h before 20-min ischemia. Co-expression of K ATP channel subunits Kir6.2/SUR1 was observed in the retinal pigment epithelium, inner segments of photoreceptors, outer plexiform and ganglion cell layers and at the border of the inner nuclear layer. In contrast to a 20- or 40-min ischemia, a 3-min ischemia induced no alteration of the electroretinogram (ERG) and constituted the preconditioning stimulus. An ischemic challenge of 40 min in preconditioned rats induced impairment of retinal function. However, animals preconditioned 24, 48 and 72 h before 20-min ischemia had a significant improvement of the ERG. (−)Cromakalim and P1060 mimicked the effect of IPC. Glipizide significantly suppressed the protective effects of preconditioning. In conclusion, activation of K ATP channels plays an important role in the mechanism of preconditioning by enhancing the resistance of the retina against a severe ischemic insult. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Brain Research Elsevier

ATP-sensitive potassium channels (K ATP ) in retina: a key role for delayed ischemic tolerance

Loading next page...
 
/lp/elsevier/atp-sensitive-potassium-channels-k-atp-in-retina-a-key-role-for-OLD3hpU4I4
Publisher
Elsevier
Copyright
Copyright © 2001 Elsevier Science B.V.
ISSN
0006-8993
D.O.I.
10.1016/S0006-8993(00)03152-8
Publisher site
See Article on Publisher Site

Abstract

The objectives of the present study were to determine the localization of K ATP channels in normal retina and to evaluate their potential roles in ischemic preconditioning (IPC) in a rat model of ischemia induced by increased intraocular pressure (IOP). Brown Norway rats were subjected to sublethal 3-, lethal 20- and 40-min ischemia and the functional recovery was evaluated using electroretinography. The time interval between ischemic insults ranged from 1 to 72 h. The effects of K ATP channel blockade on IPC protection were studied by treatment with 0.01% glipizide. IPC was mimicked by injection of K ATP channel openers of 0.01% (−)cromakalim or 0.01% P1060 72 h before 20-min ischemia. Co-expression of K ATP channel subunits Kir6.2/SUR1 was observed in the retinal pigment epithelium, inner segments of photoreceptors, outer plexiform and ganglion cell layers and at the border of the inner nuclear layer. In contrast to a 20- or 40-min ischemia, a 3-min ischemia induced no alteration of the electroretinogram (ERG) and constituted the preconditioning stimulus. An ischemic challenge of 40 min in preconditioned rats induced impairment of retinal function. However, animals preconditioned 24, 48 and 72 h before 20-min ischemia had a significant improvement of the ERG. (−)Cromakalim and P1060 mimicked the effect of IPC. Glipizide significantly suppressed the protective effects of preconditioning. In conclusion, activation of K ATP channels plays an important role in the mechanism of preconditioning by enhancing the resistance of the retina against a severe ischemic insult.

Journal

Brain ResearchElsevier

Published: Jan 26, 2001

References

  • Discrete distributions of adenosine receptors in mammalian retina
    Blazynski, C.
  • The ABCs of ATP-sensitive potassium channels: more pieces of the puzzle
    Bryan, J.; Aguilar-Bryan, L.
  • Ischemic tolerance in the brain
    Chen, J.; Simon, R.
  • The pharmacology of ATP-sensitive potassium channels
    Edwards, G.; Weston, A.H.
  • Importance of PKC and tyrosine kinase in single or multiple cycles of preconditioning in rat hearts
    Fryer, R.M.; Schultz, J.E.; Hsu, A.K.; Gross, G.J.
  • Whole cell patch-clamp recordings of rat midbrain dopaminergic neurons isolate a sulphonylurea- and ATP-sensitive component of potassium currents activated by hypoxia
    Guatteo, E.; Federici, M.; Siniscalchi, A.; Knopfel, T.; Mercuri, N.B.; Bernardi, G.
  • G protein regulation of cardiac muscarinic potassium channel
    Kurachi, Y.

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 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

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

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off