Neurovascular coupling in rat brain operates independent of hemoglobin deoxygenation

Ute Lindauer*, Christoph Leithner, Heike Kaasch, Benjamin Rohrer, Marco Foddis, Martina Füchtemeier, Nikolas Offenhauser, Jens Steinbrink, Georg Royl, Matthias Kohl-Bareis, Ulrich Dirnagl

*Corresponding author for this work
47 Citations (Scopus)


Recently, a universal, simple, and fail-safe mechanism has been proposed by which cerebral blood flow (CBF) might be coupled to oxygen metabolism during neuronal activation without the need for any tissue-based mechanism. According to this concept, vasodilation occurs by local erythrocytic release of nitric oxide or ATP wherever and whenever hemoglobin is deoxygenated, directly matching oxygen demand and supply in every tissue. For neurovascular coupling in the brain, we present experimental evidence challenging this view by applying an experimental regime operating without deoxy-hemoglobin. Hyperbaric hyperoxygenation (HBO) allowed us to prevent hemoglobin deoxygenation, as the oxygen that was physically dissolved in the tissue was sufficient to support oxidative metabolism. Regional CBF and regional cerebral blood oxygenation were measured using a cranial window preparation in anesthetized rats. Hemodynamic and neuronal responses to electrical forepaw stimulation or cortical spreading depression (CSD) were analyzed under normobaric normoxia and during HBO up to 4 ATA (standard atmospheres absolute). Inconsistent with the proposed mechanism, during HBO, CBF responses to functional activation or CSD were unchanged. Our results show that activation-induced CBF regulation in the brain does not operate through the release of vasoactive mediators on hemoglobin deoxygenation or through a tissue-based oxygen-sensing mechanism.

Original languageEnglish
JournalJournal of Cerebral Blood Flow and Metabolism
Issue number4
Pages (from-to)757-768
Number of pages12
Publication statusPublished - 01.04.2010


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