title: Simultaneous two-photon imaging of oxygen and blood flow in deep cerebral vessels.
abstract: Uncovering principles that regulate energy metabolism in the brain requires mapping of partial pressure of oxygen (PO(2)) and blood flow with high spatial and temporal resolution. Using two-photon phosphorescence lifetime microscopy (2PLM) and the oxygen probe PtP-C343, we show that PO(2) can be accurately measured in the brain at depths up to 300 μm with micron-scale resolution. In addition, 2PLM allowed simultaneous measurements of blood flow and of PO(2) in capillaries with less than one-second temporal resolution. Using this approach, we detected erythrocyte-associated transients (EATs) in oxygen in the rat olfactory bulb and showed the existence of diffusion-based arterio-venous shunts. Sensory stimulation evoked functional hyperemia, accompanied by an increase in PO(2) in capillaries and by a biphasic PO(2) response in the neuropil, consisting of an 'initial dip' and a rebound. 2PLM of PO(2) opens new avenues for studies of brain metabolism and blood flow regulation.
authors.affiliation: Institut National de Santé et de Recherche Médicale (INSERM), U603, Paris, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lecoq
authors.forename: Alexandre
authors.initials: A
authors.lastname: Parpaleix
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Roussakis
authors.forename: Mathieu
authors.initials: M
authors.lastname: Ducros
authors.forename: Yannick
authors.initials: Y
authors.lastname: Goulam Houssen
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Vinogradov
authors.forename: Serge
authors.initials: S
authors.lastname: Charpak
mesh_terms: D000818:Animals; D002196:Capillaries / Q000378:metabolism; D002536:Cerebral Arteries / Q000378:metabolism / Q000502:physiology; D002550:Cerebral Veins / Q000378:metabolism / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology; D008163:Luminescent Measurements / Q000379:methods; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D009830:Olfactory Bulb / Q000098:blood supply / Q000378:metabolism; D055696:Olfactory Perception / Q000502:physiology; D010100:Oxygen / Q000378:metabolism*; D010313:Partial Pressure; D051381:Rats; D017208:Rats, Wistar
chemical_list: D010100:Oxygen