N-Acetylaspartate distribution in rat brain striatum during acute brain ischemia
| Autor: | Maj Hedehus, Anders Stensgaard, Simon Topp, Henning Laursen, Thomas N. Sager, Sverre Rosenbaum, Jacob S. Valsborg, Anker Jon Hansen, Anders Fink-Jensen |
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| Rok vydání: | 1999 |
| Předmět: |
Male
Microdialysis medicine.medical_specialty Pathology Magnetic Resonance Spectroscopy Ischemia Striatum 030218 nuclear medicine & medical imaging Brain Ischemia Brain ischemia Rats Sprague-Dawley 03 medical and health sciences 0302 clinical medicine Interstitial space immune system diseases In vivo medicine.artery Internal medicine mental disorders Medicine Animals Mannitol Tissue Distribution Aspartic Acid business.industry Osmolar Concentration Cerebral Infarction medicine.disease Corpus Striatum nervous system diseases Rats Endocrinology nervous system Neurology Middle cerebral artery Acute Disease Neurology (clinical) Cardiology and Cardiovascular Medicine business 030217 neurology & neurosurgery medicine.drug |
| Zdroj: | Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. 19(2) |
| ISSN: | 0271-678X |
| Popis: | Brain N-acetylaspartate (NAA) can be quantified by in vivo proton magnetic resonance spectroscopy (1H-MRS) and is used in clinical settings as a marker of neuronal density. It is, however, uncertain whether the change in brain NAA content in acute stroke is reliably measured by 1H-MRS and how NAA is distributed within the ischemic area. Rats were exposed to middle cerebral artery occlusion. Preischemic values of [NAA] in striatum were 11 mmol/L by 1H-MRS and 8 mmol/kg by HPLC. The methods showed a comparable reduction during the 8 hours of ischemia. The interstitial level of [NAA] ([NAA]e) was determined by microdialysis using [3H]NAA to assess in vivo recovery. After induction of ischemia, [NAA]e increased linearly from 70 µmol/L to a peak level of 2 mmol/L after 2 to 3 hours before declining to 0.7 mmol/L at 7 hours. For comparison, [NAA]e was measured in striatum during global ischemia, revealing that [NAA]e increased linearly to 4 mmol/L after 3 hours and this level was maintained for the next 4 h. From the change in in vivo recovery of the interstitial space volume marker [14C]mannitol, the relative amount of NAA distributed in the interstitial space was calculated to be 0.2% of the total brain NAA during normal conditions and only 2 to 6% during ischemia. It was concluded that the majority of brain NAA is intracellularly located during ischemia despite large increases of interstitial [NAA]. Thus, MR quantification of NAA during acute ischemia reflects primarily changes in intracellular levels of NAA. |
| Databáze: | OpenAIRE |
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