OxTalks is Changing
OxTalks will soon move to the new Halo platform and will become 'Oxford Events.' There will be a need for an OxTalks freeze. This was previously planned for Friday 14th November – a new date will be shared as soon as it is available (full details will be available on the Staff Gateway).
In the meantime, the OxTalks site will remain active and events will continue to be published.
If staff have any questions about the Oxford Events launch, please contact halo@digital.ox.ac.uk
Hypoxia and cerebral perfusion in the mammalian brain
During acute hypoxia, increases in cerebral blood flow maintain brain oxygen delivery. In vitro and in vivo experiments conducted in rodent models show that during hypoxia, cortical astrocytes produce the potent vasodilator nitric oxide (NO) via nitrite reduction in mitochondria. Inhibition of mitochondrial respiration mimics, but also occludes, the effect of hypoxia on NO production in astrocytes. Astrocytes display high expression of the molybdenum-cofactor-containing mitochondrial enzyme sulfite oxidase, which can catalyze nitrite reduction in hypoxia. Replacement of molybdenum with tungsten or knockdown of sulfite oxidase expression in astrocytes blocks hypoxia-induced NO production by these glial cells and reduces the cerebrovascular response to hypoxia. These data identify astrocyte mitochondria as brain oxygen sensors that regulate cerebral blood flow during hypoxia via release of nitric oxide. Methods to study cerebral perfusion and hypoxia in rodents will also be discussed, with a particular focus on the physiological interpretation of MRI methods.
SPEAKER BIOGRAPHY
Isabel undertook a PhD at the Centre for Advanced Biomedical Imaging (CABI) in UCL working with Jack Wells and Mark Lythgoe to use fMRI, arterial spin labelling and optogenetics to study brain blood flow. Next Isabel undertook a post-doctoral research position with Alexander Gourine at the Centre for Cardiovascular and Metabolic Neuroscience (CCMN) also at UCL. In 2021 Isabel relocated to Sheffield soon after the birth of her third child. In 2024 Isabel received a wellcome trust career development award to study the use of hyperpolarised xenon for non-invasive brain oximetry.
Date:
23 January 2026, 13:00
Venue:
Sherrington Library, off Parks Road OX1 3PT
Venue Details:
Sherrington Building
Speaker:
Dr Isabel Christie (University of Sheffield)
Organising department:
Department of Physiology, Anatomy and Genetics (DPAG)
Organisers:
Dr Thomas Keeley (DPAG, University of Oxford),
Dr Mootaz Salman (DPAG, University of Oxford)
Organiser contact email address:
events@dpag.ox.ac.uk
Host:
Dr Tom Keeley (DPAG, University of Oxford)
Part of:
DPAG Head of Department Seminar Series
Booking required?:
Not required
Audience:
Members of the University only
Editor:
Hannah Simm
