Responses to Cortical Spreading Depression under Oxygen Deficiency



J Sonn*, A Mayevsky
The Mina & Everard Goodman, Faculty of Life Sciences and Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University RAMAT-GAN 52900, Israel


Article Metrics

CrossRef Citations:
0
Total Statistics:

Full-Text HTML Views: 952
Abstract HTML Views: 346
PDF Downloads: 118
Total Views/Downloads: 1416
Unique Statistics:

Full-Text HTML Views: 410
Abstract HTML Views: 207
PDF Downloads: 97
Total Views/Downloads: 714



© Sonn and Mayevsky; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Faculty of Life Sciences Bar- Ilan University RAMAT-GAN 52900, Israel; Tel: 972-3-5317558; Fax: 972-3-5352184; E-mail: sonnju1@gmail.com


Abstract

Objectives:

Objectives: The effect of cortical spreading depression (CSD) on extracellular K+ concentrations ([K+]e), cerebral blood flow (CBF), mitochondrial NADH redox state and direct current (DC) potential was studied during normoxia and three pathological conditions: hypoxia, after NOS inhibition by L-NAME and partial ischemia.

Methods:

A special device (MPA) was used for monitoring CSD wave propagation, containing: mitochondrial NADH redox state and reflected light, by a fluorometry technique; DC potential by Ag/AgCl electrodes; CBF by laser Doppler flowmetry; and [K+]e by a mini-electrode.

Results and Discussion:

  1. CSD under the 3 pathological conditions caused an initial increase in NADH and a further decrease in CBF during the first phase of CSD, indicating an imbalance between oxygen supply and demand as a result of the increase in oxygen requirements.
  2. The hyperperfusion phase in CBF was significantly reduced during hypoxia and ischemia showing a further decline in oxygen supply during CSD.
  3. CSD wave duration increased during the pathological conditions, showing a disturbance in energy production.
  4. Extracellular K+ levels during CSD, increased to identical levels during normoxia and during the three pathological groups, indicating correspondingly increase in oxygen demand. 5. The special design of the MPA enabled identifying differences in the simultaneous responses of the measured parameters, which may indicate changes in the interrelation between oxygen demand, oxygen supply and oxygen balance during CSD propagation, under the conditions tested. 6. In conclusion, brain oxygenation was found to be a critical factor in the responses of the brain to CSD.
Keywords: Brain oxygenation, cerebral blood flow, extracellular K+, hypoxia, mitochondrial NADH, nitric oxide synthase inhibition, partial ischemia.