Institut National de Santé et de Recherche Médicale (INSERM) U603, Paris, France.
Nat Med. 2013 Feb;19(2):241-6. doi: 10.1038/nm.3059. Epub 2013 Jan 13.
Two-photon phosphorescence lifetime microscopy (2PLM) has been used recently for depth measurements of oxygen partial pressure (PO(2)) in the rodent brain. In capillaries of olfactory bulb glomeruli, 2PLM has also allowed simultaneous measurements of PO(2) and blood flow and revealed the presence of erythrocyte-associated transients (EATs), which are PO(2) gradients that are associated with individual erythrocytes. We investigated the extent to which EAT properties in capillaries report local neuronal activity. We find that at rest, PO(2) at EAT peaks overestimates the mean PO(2) by 35 mm Hg. PO(2) between two EAT peaks is at equilibrium with, and thus reports, PO(2) in the neuropil. During odor stimulation, there is a small PO(2) decrease before functional hyperemia, showing that the initial dip in PO(2) is present at the level of capillaries. We conclude that imaging oxygen dynamics in capillaries provides a unique and noninvasive approach to map neuronal activity.
双光子荧光寿命显微镜（2PLM）最近已被用于测量啮齿动物大脑中氧分压（PO2）的深度。在嗅球肾小球的毛细血管中，2PLM 还允许同时测量 PO2 和血流，并揭示了红细胞相关瞬变（EAT）的存在，即与单个红细胞相关的 PO2 梯度。我们研究了毛细血管中 EAT 特性在多大程度上报告局部神经元活动。我们发现，在休息状态下，EAT 峰处的 PO2 高估了平均 PO2 约 35 mmHg。两个 EAT 峰之间的 PO2 处于平衡状态，因此报告神经胶内的 PO2。在气味刺激期间，在功能性充血之前会出现较小的 PO2 下降，表明 PO2 的初始下降出现在毛细血管水平。我们得出的结论是，对毛细血管中氧气动态的成像提供了一种独特的、非侵入性的方法来绘制神经元活动。
