抄録
Chronic hypoxia provokes morphological and functional adaptations of the brain microcirculaton, such as angiogenesis and regulation of blood flow. In the mouse cortex, parenchymal capillary significantly dilates after 1-week hypoxia to facilitate an exchange of oxygen with tissue. A vessel sprout appears during 1-2 week hypoxia and creates a new vessel connection. A net contribution of the new vessels to the oxygen delivery may be limited, but effective for a local spot of oxygen deficiency. Because brain vasculature is surrounded with a variety of cells, such as pericytes, astrocytes, and microglias, these perivascular cells may participate in a process of the angiogenesis differently at each step; sprout, extension, connection, and normalization. Depending on cell types, oxygen environment may not be uniform as variable distances from the nearest vasculature. This indicates that the mechanism for oxygen sensing in the cells might not necessarily be common among the cells. Chronic hypoxia attenuates the response of the cortical arteries to neural activation, leading to a reduction of activity-dependent blood flow increases. This adaptation might be important for further understanding the role of neurovascular coupling in maintaining the functional plasticity of the central nervous system.
