J Korean Neurotraumatol Soc.  2011 Apr;7(1):1-7. 10.13004/jknts.2011.7.1.1.

Evaluating the Extent of Ischemic Insult on Hippocampal Slices by Using Antidromic Recordings

Affiliations
  • 1Department of Neurosurgery, Korea University Guro Hospital, Seoul, Korea. ykapa76@yahoo.co.kr

Abstract


OBJECTIVE
Energy failure and concurrent electrical silence are common features of oxygen-glucose deprivation (OGD) in the brain. Hippocampal slice has been used extensively to study electrophysiological alterations. Orthodromic extracellular field potential recording has been most widely chosen for those studies however there were few with antidromic recording. The goal of this study is to clarify which types of recordings is better for the evaluation of extent of ischecmic insults.
METHODS
Rat hippocampal slices were made for the orthodromically and antidromically evoked filed potential recording. Before, during and after 6 to 11 minutes of experimental OGD, the authors measured population spike amplitude and slope of field excitatory postsynaptic potential (fEPSP).
RESULTS
A dramatic reduction of amplitude and total disappearance of orthodromic population spike (oPS) noted 1.1 +/- 0.2 min after OGD onset. On the contrary antidromic population spike (aPS) was not affected at the beginning. It slowly and gradually diminished and finally disappeared 6.6 +/- 0.2 min after OGD onset. A transient recovery of oPS, so called hypoxic injury potentials (HIP) briefly occurred just before the total dissappearance of aPS and the both signals disappeared simultaneously. Incomplete recovery due to irreversible damage began 7 min after OGD onset. There was no recovery 10 min after OGD, 7 min after oPS loss and 2 min after aPS loss. The OGD experiments with various neuroprotective agents (MK 801, AP-5, lidocaine, CNQX, adenosine) lasted for longer than 2 min after aPS disappearance sensitively showed their efficacy.
CONCLUSION
These results show that observation for aPS after OGD provides more accurate timing of irreversible damage than those for oPS data or for the duration of OGD.

Keyword

Antidromic recording; Orthodromic recording; Oxygen glucose deprivation; Hippocampal slice preparation

MeSH Terms

6-Cyano-7-nitroquinoxaline-2,3-dione
Animals
Brain
Excitatory Postsynaptic Potentials
Lidocaine
Neuroprotective Agents
Rats
6-Cyano-7-nitroquinoxaline-2,3-dione
Lidocaine
Neuroprotective Agents
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