Effect of barbiturates on hydroxyl radicals, lipid peroxidation, and hypoxic cell death in human NT2-N neurons

Runar Almaas, Ola D. Saugstad, David E Pleasure, Terje Rootwelt

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Abstract

Background: Barbiturates have been shown to be neuroprotective in several animal models, but the underlying mechanisms are unknown. In this study, the authors investigated the effect of barbiturates on free radical scavenging and attempted to correlate this with their neuroprotective effects in a model of hypoxic cell death in human NT2-N neurons. Methods: Hydroxyl radicals were generated by ascorbic acid and iron and were measured by conversion of salicylate to 2,3-dihydroxybenzoic acid. The effect of barbiturates on lipid peroxidation measured as malondialdehyde and 4- hydroxynon-2-enal was also investigated. Hypoxia studies were then performed on human NT2-N neurons. The cells were exposed to 10 h of hypoxia or combined oxygen and glucose deprivation for 3 or 5 h in the presence of thiopental (50-600 μM), methohexital (50-400 μM), phenobarbital (10-400 μM), or pentobarbital (10-400 μM), and cell death was evaluated after 24 h by lactate dehydrogenase release. Results: Pentobarbital, phenobarbital, methohexital, and thiopental dose-dependently inhibited formation of 2,3- dihydroxybenzoic acid and iron-stimulated lipid peroxidation. There were significant but moderate differences in antioxidant action between the barbiturates. While phenobarbital (10-400 μM) and pentobarbital (10-50 μM) increased lactate dehydrogenase release after combined oxygen and glucose deprivation, thiopental and methohexital protected the neurons at all tested concentrations. At a higher concentration (400 μM), pentobarbital also significantly protected the neurons. At both 50 and 400 μM, thiopental and methohexital protected the NT2-N neurons significantly better than phenobarbital and pentobarbital. Conclusions: Barbiturates differ markedly in their neuroprotective effects against combined oxygen and glucose deprivation in human NT2-N neurons. The variation in neuroprotective effects could only partly be explained by differences in antioxidant action.

Original languageEnglish (US)
Pages (from-to)764-774
Number of pages11
JournalAnesthesiology
Volume92
Issue number3
StatePublished - Mar 2000
Externally publishedYes

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Keywords

  • Antioxidants
  • Dizocilpine
  • Free radicals
  • In vitro

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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