This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Abraini, J. H. Articles by Lemaire, M. Search for Related Content PubMed PubMed Citation Articles by Abraini, J. H. Articles by Lemaire, M.

---

LETTER TO THE EDITOR

Postischemic Nitrous Oxide Alone Versus Intraischemic Nitrous Oxide in the Presence of Isoflurane: What It May Change for Neuroprotection Against Cerebral Stroke in the Rat

Université de Caen, France; Air Liquide Research Center; Jouy-en-Josas, France; abraini{at}neuro.unicaen.fr

To the Editor:

Warner et al. (1) found no neuroprotective effect of intraischemic nitrous oxide in rats anesthetized with isoflurane. We would like to draw the authors’ attention regarding our finding of a neuroprotective action of postischemic subanesthetic nitrous oxide (0.6 minimum anesthetic concentration) in freely moving, thereby physiologically self-regulated, awake rats compared with control animals treated with postischemic medical air in similar environmentally controlled conditions (2). Differences in neuroprotection between postischemic nitrous oxide alone (2,3) and intraischemic nitrous oxide-isoflurane (1) and convergences in neuroprotection between postischemic xenon alone and intraischemic xenon-isoflurane (2–4) are likely attributable to the respective interactions of nitrous oxide and xenon with isoflurane. Indeed, neither nitrous oxide nor xenon alone induced apoptosis; however, when given with isoflurane in neonatal rats, nitrous oxide enhanced, whereas xenon inhibited, isoflurane-induced apoptosis (5). Whether such an adverse interaction between nitrous oxide and isoflurane occurs in young adult rats subjected to transient cerebral ischemia, this may counteract the neuroprotective antagonistic action of nitrous oxide at the N-methyl-d-aspartate receptor (6). Finally, further support for a neuroprotective action of postischemic nitrous oxide alone on histologic outcome is that post-treatment with nitrous oxide (or xenon) reduces neuronal death induced by intracerebral injection of N-methyl-d-aspartate in awake rats (7).

References

1. Yokoo N, Sheng H, Mixco J, et al. Intraischemic nitrous oxide alters neither neurologic nor histologic outcome: A comparison with dizocilpine. Anesth Analg 2004;99:896–903.[Abstract/Free Full Text]
2. David HN, Leveille F, Chalzaviel L, et al. Reduction of ischemic brain damage by nitrous oxide and xenon. J Cereb Blood Flow Metab 2003;23:1168–73.[Web of Science][Medline]
3. Abraini JH, David HN, Nicole O, et al. Neuroprotection by nitrous oxide and xenon and its relation to minimum alveolar concentration. Anesthesiology 2004;101:260–1.[Medline]
4. Homi HM, Yokoo N, Ma D, Warner DS, et al. The neuroprotective effect of xenon administration during transient middle cerebral artery occlusion in mice. Anesthesiology 2003;99:876–81.[Web of Science][Medline]
5. Williamson PB, Ma D, Hossain M, et al. Xenon does not cause apoptotic neurodegeneration in the neonatal rat and protects against isoflurane-induced apoptosis. Anesthesiology 2004;101:A864.
6. Jevtovic-Todorovic V, Todorovic SM, Mennerick S, et al. Nitrous oxide (laughing gas) is an NMDA antagonist, neuroprotectant and neurotoxin. Nat Med 1998;4:460–3.[Web of Science][Medline]
7. Abraini JH, Lemaire M, David HN. Potentially neuroprotective and therapeutic properties of nitrous oxide and xenon. In: Slikker W Jr, Trembly B, Andrew R, eds. Seventh International Conference on Neuroprotective Agents. Ann N Y Acad Sci.

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Abraini, J. H. Articles by Lemaire, M. Search for Related Content PubMed PubMed Citation Articles by Abraini, J. H. Articles by Lemaire, M.