Oxygen modulation of neurovascular coupling in the retina

Neurovascular coupling is a process through which neuronal activity leads to local increases in blood flow in the central nervous system. In brain slices, 100% O2 has been shown to alter neurovascular coupling, suppressing activity-dependent vasodilation. However, in vivo, hyperoxia reportedly has n...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2011-10, Vol.108 (43), p.17827-17831
Main Authors: Mishra, Anusha, Hamid, Arif, Newman, Eric A
Format: Article
Language:English
Subjects:
adults
Animals
Arterioles
Biological Sciences
Blood
Blood flow
Blood vessels
Brain
Brain slice preparation
Cell Hypoxia - physiology
Central nervous system
Electrodes
Eyes & eyesight
Hyperoxia
Male
mercury
Microelectrodes
Neonates
Nervous system
Neuroglia
Neuromodulation
Neurons
Nutrients
Oxygen
Oxygen - metabolism
Partial Pressure
Photic Stimulation
Rats
Rats, Long-Evans
Retina
Retinal Neurons - metabolism
Retinal Vessels - metabolism
Rodents
Signal Transduction - physiology
Statistics, Nonparametric
Vasoconstriction
Vasoconstriction - physiology
Vasodilation
Vasodilation - physiology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Neurovascular coupling is a process through which neuronal activity leads to local increases in blood flow in the central nervous system. In brain slices, 100% O2 has been shown to alter neurovascular coupling, suppressing activity-dependent vasodilation. However, in vivo, hyperoxia reportedly has no effect on blood flow. Resolving these conflicting findings is important, given that hyperoxia is often used in the clinic in the treatment of both adults and neonates, and a reduction in neurovascular coupling could deprive active neurons of adequate nutrients. Here we address this issue by examining neurovascular coupling in both ex vivo and in vivo rat retina preparations. In the ex vivo retina, 100% O2 reduced light-evoked arteriole vasodilations by 3.9-fold and increased vasoconstrictions by 2.6-fold. In vivo, however, hyperoxia had no effect on light-evoked arteriole dilations or blood velocity. Oxygen electrode measurements showed that 100% O2 raised pO2 in the ex vivo retina from 34 to 548 mm Hg, whereas hyperoxia has been reported to increase retinal pO2 in vivo to only ∼53 mm Hg [Yu DY, Cringle SJ, Alder VA, Su EN (1994) Am J Physiol 267:H2498-H2507]. Replicating the hyperoxic in vivo pO2 of 53 mm Hg in the ex vivo retina did not alter vasomotor responses, indicating that although O2 can modulate neurovascular coupling when raised sufficiently high, the hyperoxia-induced rise in retinal pO2 in vivo is not sufficient to produce a modulatory effect. Our findings demonstrate that hyperoxia does not alter neurovascular coupling in vivo, ensuring that active neurons receive an adequate supply of nutrients.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1110533108