Institut National de Santé et de Recherche Médicale (INSERM), U603, Paris, France.
Nat Med. 2011 Jun 5;17(7):893-8. doi: 10.1038/nm.2394.
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.
揭示大脑能量代谢的调控原理需要以高时空分辨率对氧分压(PO2)和血流进行映射。我们使用双光子磷光寿命显微镜(2PLM)和氧探针 PtP-C343,展示了在深度达 300μm 的大脑中,以微米级分辨率可准确测量 PO2。此外,2PLM 允许以小于一秒的时间分辨率,对毛细血管中的血流和 PO2 进行同时测量。我们利用这种方法,在大鼠嗅球中检测到了与红细胞相关的氧瞬变(EAT),并证实了基于扩散的动静脉短路的存在。感觉刺激引发功能性充血,伴随着毛细血管中 PO2 的增加,以及神经间质中 PO2 的双相反应,包括“初始下降”和反弹。PO2 的 2PLM 为研究大脑代谢和血流调节开辟了新途径。