This Article Full Text Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kanthan, R. Articles by Miyashita, H. Search for Related Content PubMed PubMed Citation Articles by Kanthan, R. Articles by Miyashita, H.

(Stroke. 1995;26:870-873.)
© 1995 American Heart Association, Inc.

Articles

Intracerebral Human Microdialysis

In Vivo Study of an Acute Focal Ischemic Model of the Human Brain

R. Kanthan, MD, FRCS; A. Shuaib, MD, FRCPC; R. Griebel, MD, FRCSC H. Miyashita, BSc

From the Departments of Medicine (Neurology) (A.S.) and Surgery (Neurosurgery) (R.G.) and the Saskatchewan Stroke Research Centre (R.K., H.M.), Saskatoon, Saskatchewan, Canada.

Background and Purpose In vivo microdialysis was introduced in 1982 as a technique to study cerebral neurochemistry in awake, freely moving animals. In small animals, bilateral carotid occlusion produces a 7- to 10-fold increase in extracellular glutamate concentrations. This rapidly falls with reperfusion. Increase in extracellular glutamate is currently believed to be a major factor in initiating neuronal injury. Glutamate antagonists are currently undergoing clinical trials in acute stroke. Human data on the extracellular levels of glutamate and other amino acids in the normal or ischemic brain are limited. In this communication we wish to report the extracellular concentrations of glutamate, serine, glutamine, glycine, taurine, alanine, and -aminobutyric acid, as monitored by in vivo microdialysis, in the simulated ischemic model of the temporal lobe of the human brain.

Methods Intracerebral microdialysis was carried out in five patients who underwent resection of the temporal lobe for intractable epilepsy. Surgical excision leads to an acute (from partial to total, ie, from incomplete to complete) ischemic state of the resected brain. This was our model to study the changes in human extracellular fluid during acute focal ischemic conditions.

Results Extracellular glutamate concentrations were 15 to 30 µmol/L in the preischemic samples. This increased to 380.69±42.14 µmol/L with partial (incomplete) ischemia and reached a peak of 1781.67±292.34 µmol/L (>100-fold) with total isolation of the temporal pole (complete ischemia). The levels fell to 394.52±72.93 µmol/L 20 minutes after resection. Similar trends were observed with the onset of ischemia in the dialysate levels of serine, glutamine, glycine, alanine, taurine, and -aminobutyric acid.

Conclusions Our results show that there is a significant increase in extracellular glutamate and other neurotransmitters with ischemia in the temporal lobe model of the human brain. This increase is of a higher magnitude than that in small animals.

Key Words: amino acids • neurochemistry • cerebral ischemia

This article has been cited by other articles:

				C. Berger, W.-R. Schabitz, D. Georgiadis, T. Steiner, A. Aschoff, and S. Schwab Effects of Hypothermia on Excitatory Amino Acids and Metabolism in Stroke Patients: A Microdialysis Study Stroke, February 1, 2002; 33(2): 519 - 524. [Abstract] [Full Text] [PDF]

				P J Hutchinson, M T O'Connell, P G Al-Rawi, C R Kett-White, A K Gupta, L B Maskell, J D Pickard, and P J Kirkpatrick Increases in GABA concentrations during cerebral ischaemia: a microdialysis study of extracellular amino acids J. Neurol. Neurosurg. Psychiatry, January 1, 2002; 72(1): 99 - 105. [Abstract] [Full Text] [PDF]

				S. Schneweis, M. Grond, F. Staub, G. Brinker, M. Neveling, C. Dohmen, R. Graf, W.-D. Heiss, and A. Shuaib Predictive Value of Neurochemical Monitoring in Large Middle Cerebral Artery Infarction Editorial Comment Stroke, August 1, 2001; 32(8): 1863 - 1867. [Abstract] [Full Text] [PDF]

				J. Serena, R. Leira, J. Castillo, J. M. Pumar, M. Castellanos, and A. Davalos Neurological Deterioration in Acute Lacunar Infarctions : The Role of Excitatory and Inhibitory Neurotransmitters Stroke, May 1, 2001; 32(5): 1154 - 1161. [Abstract] [Full Text] [PDF]

				Y. Pu, Q.-F. Li, C.-M. Zeng, J. Gao, J. Qi, D.-X. Luo, S. Mahankali, P. T. Fox, and J.-H. Gao Increased Detectability of Alpha Brain Glutamate/Glutamine in Neonatal Hypoxic-Ischemic Encephalopathy AJNR Am. J. Neuroradiol., January 1, 2000; 21(1): 203 - 212. [Abstract] [Full Text] [PDF]

				A Mendelowitsch, G W Mergner, A Shuaib, and L N Sekhar Cortical brain microdialysis and temperature monitoring during hypothermic circulatory arrest in humans J. Neurol. Neurosurg. Psychiatry, May 1, 1998; 64(5): 611 - 618. [Abstract] [Full Text] [PDF]

				J. Castillo, A. Davalos, J. Naveiro, and M. Noya Neuroexcitatory Amino Acids and Their Relation to Infarct Size and Neurological Deficit in Ischemic Stroke Stroke, June 1, 1996; 27(6): 1060 - 1065. [Abstract] [Full Text]