gms | German Medical Science

55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

25. bis 28.04.2004, Köln

Amino acid release in ischemic rat hippocampal brain slices under the influence of methohexital

Aminosäurefreisetzung in ischämischen Hippokampusschnitten der Ratte unter dem Einfluss von Methohexital

Meeting Abstract

  • corresponding author Johannes Wölfer - Klinik und Poliklinik für Neurochirurgie am Universitätsklinikum Münster, Münster
  • I. Slottosch - Klinik und Poliklinik für Neurochirurgie am Universitätsklinikum Münster, Münster
  • C. Greiner - Klinik und Poliklinik für Neurochirurgie am Universitätsklinikum Münster, Münster
  • E.-J. Speckmann - Institut für Physiologie der Westfälische Wilhelms-Universität Münster, Münster
  • H. Wassmann - Klinik und Poliklinik für Neurochirurgie am Universitätsklinikum Münster, Münster

Deutsche Gesellschaft für Neurochirurgie. Ungarische Gesellschaft für Neurochirurgie. 55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie. Köln, 25.-28.04.2004. Düsseldorf, Köln: German Medical Science; 2004. DocDI.04.04

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2004/04dgnc0182.shtml

Veröffentlicht: 23. April 2004

© 2004 Wölfer et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective

Methohexital is commonly used as a neuroprotectant in clinical situations of diminished brain perfusion. Former experiments have shown a favourable electrophysiologic effect in vitro. Barbiturates are known to possess a GABAergic effect for themselves. On the other hand, changes of neurotransmitter release are another possible mechanism by which barbiturates could exert their neuroprotective effects. We asked whether ischemic brain tissue shows changes in the interstitial release of amino acids, especially neurotransmitters, under the influence of methohexital.

Methods

Rat hippocampal brain slices were kept in an interface (gaseous/aqueous phase) in vitro environment. DC and evoked potentials were registered together with sampling of intercellular fluid by in vitro microdialysis. Ischemia was simulated by simultaneous withdrawal of oxygen and glucose. Methohexital concentrations of 40 (n=8), 90 (n=6), and 140 μmol/l (n=7) were applied, and each experiment was pair-matched with a control. Latency and amplitude of anoxic depolarization as well as postischemic recovery of evoked potentials were studied, while 5 min-microdialysis samples were examined for a range of amino acids including major neurotransmitters by HPLC.

Results

Typical changes of electrophysiologic as well as biochemical measurements are demonstrated in the slices as soon as ischemia is induced. Methohexital, however, did not change either kinetics or spectrum of amino acid release in any of the applied concentrations, nor did it alter the electrophysiologic response to ischemic stress.

Conclusions

Our model was not able to show significant barbiturate-dependent changes of the release characteristics of so-called excitotoxic amino acids in particular. Therefore the inherent GABAergic activity of barbiturates remains one of the more likely ways by which these drugs act neuroprotectively.