Leithner 2014 J Cereb Blood Flow Metab
| Leithner C, Royl G (2014) The oxygen paradox of neurovascular coupling. J Cereb Blood Flow Metab 34:19-29. https://doi.org/10.1038/jcbfm.2013.181 |
Leithner C, Royl G (2014) J Cereb Blood Flow Metab
Abstract: The coupling of cerebral blood flow (CBF) to neuronal activity is well preserved during evolution. Upon changes in the neuronal activity, an incompletely understood coupling mechanism regulates diameter changes of supplying blood vessels, which adjust CBF within seconds. The physiologic brain tissue oxygen content would sustain unimpeded brain function for only 1 second if continuous oxygen supply would suddenly stop. This suggests that the CBF response has evolved to balance oxygen supply and demand. Surprisingly, CBF increases surpass the accompanying increases of cerebral metabolic rate of oxygen (CMRO2). However, a disproportionate CBF increase may be required to increase the concentration gradient from capillary to tissue that drives oxygen delivery. However, the brain tissue oxygen content is not zero, and tissue pO2 decreases could serve to increase oxygen delivery without a CBF increase. Experimental evidence suggests that CMRO2 can increase with constant CBF within limits and decreases of baseline CBF were observed with constant CMRO2. This conflicting evidence may be viewed as an oxygen paradox of neurovascular coupling. As a possible solution for this paradox, we hypothesize that the CBF response has evolved to safeguard brain function in situations of moderate pathophysiological interference with oxygen supply.
• Bioblast editor: Gnaiger E
Selected quotes
- The average capillary oxygen tension in the brain is around 40 to 50 mm Hg [10] {5.3 to 6.7 kPa}. The average brain tissue pO2 is around 20 to 30 mm Hg [11, 12, 13, 14, 15] {2.7 to 4.0 kPa} with little differences between species [16].
Labels: MiParea: Respiration
Stress:Hypoxia Organism: Human, Mouse, Rat Tissue;cell: Nervous system Preparation: Intact organism
