Takano Takahiro, Tian Guo-Feng, Peng Weiguo, Lou Nanhong, Libionka Witold, Han Xiaoning, Nedergaard Maiken
Center for Aging and Developmental Biology, Department of Neurosurgery, University of Rochester Medical School, 601 Elmwood Avenue, Rochester, New York 14642, USA.
Nat Neurosci. 2006 Feb;9(2):260-7. doi: 10.1038/nn1623. Epub 2005 Dec 25.
Local increase in blood flow during neural activity forms the basis for functional brain imaging, but its mechanism remains poorly defined. Here we show that cortical astrocytes in vivo possess a powerful mechanism for rapid vasodilation. We imaged the activity of astrocytes labeled with the calcium (Ca(2+))-sensitive indicator rhod-2 in somatosensory cortex of adult mice. Photolysis of caged Ca(2+) in astrocytic endfeet ensheathing the vessel wall was associated with an 18% increase in arterial cross-section area that corresponded to a 37% increase in blood flow. Vasodilation occurred with a latency of only 1-2 s, and both indomethacin and the cyclooxygenase-1 inhibitor SC-560 blocked the photolysis-induced hyperemia. These observations implicate astrocytes in the control of local microcirculation and suggest that one of their physiological roles is to mediate vasodilation in response to increased neural activity.
神经活动期间局部血流增加构成了功能性脑成像的基础，但其机制仍不清楚。在这里，我们表明成年小鼠体感皮层中的皮质星形胶质细胞具有强大的快速血管舒张机制。我们对用钙（Ca(2+)）敏感指示剂罗丹明-2标记的星形胶质细胞在成年小鼠体感皮层中的活动进行了成像。在包绕血管壁的星形胶质细胞终足中光解笼锁Ca(2+)与动脉横截面积增加18%相关，这对应于血流量增加37%。血管舒张仅在1-2秒的延迟后发生，吲哚美辛和环氧合酶-1抑制剂SC-560均阻断了光解诱导的充血。这些观察结果表明星形胶质细胞参与局部微循环的控制，并表明它们的生理作用之一是响应神经活动增加介导血管舒张。
