Effects of hypothermic metabolic suppression on hippocampal glutamate concentrations after transient global cerebral ischemia

U. M. Illievich, M. H. Zornow, Taek Choi Kyu Taek Choi, M. S. Scheller, M. A.P. Strnat

Research output: Contribution to journalArticlepeer-review

85 Scopus citations

Abstract

The cerebroprotective effects of mild and moderate hypothermia cannot be explained solely by a temperature-induced decrease in cerebral metabolic rate. This study examined the effects of graded hypothermia (32°C, 28°C, and 22°C, vs 38°C) on periischemic extracellular hippocampal glutamate concentrations in the New Zealand White rabbit. Global cerebral ischemia (15 min) was produced by a combination of neck tourniquet inflation and induction of systemic hypotension. Glutamate, an important mediator of ischemic neuronal injury, was measured using in vivo microdialysis and high- performance liquid chromatography. Mean extracellular glutamate concentrations increased by 11 μM in the 38°C group during the ischemic period. Glutamate increased by <1 μM in the 32°C and 28°C groups and by 3 μM in the 22°C group. Thus, mild degrees of hypothermia profoundly reduced glutamate release during ischemia. This reduction greatly exceeded the estimated temperature-induced decrease in cerebral metabolic rate. We conclude that hypothermic inhibition of glutamate release during episodes of transient ischemia may significantly contribute to neuronal protection.

Original languageEnglish (US)
Pages (from-to)905-911
Number of pages7
JournalAnesthesia and analgesia
Volume78
Issue number5
DOIs
StatePublished - 1994
Externally publishedYes

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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