Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
J Cereb Blood Flow Metab. 2011 Sep;31(9):e1-10. doi: 10.1038/jcbfm.2011.96. Epub 2011 Jul 6.
Activation of astrocytic metabotropic glutamate receptor 5 (mGluR5) is postulated to elicit calcium transients, triggering a chain of events that ultimately regulates cerebral blood flow by changing the tone of smooth muscle cells of nearby arterioles. Using concurrent in vivo optical imaging and determination of receptor occupancy with (11)C-ABP688, we report here that blocking ∼80% of mGluR5 in vivo does not affect transient hemodynamic responses on brief whisker stimulations while transiently reducing neuronal activity as measured by voltage-sensitive dye imaging. Our results show that mechanisms other than activation of mGluR5 are required to trigger the initial hemodynamic response in normal physiological conditions.
星形胶质细胞代谢型谷氨酸受体 5（mGluR5）的激活被认为会引发钙离子瞬变，触发一系列事件，最终通过改变附近小动脉平滑肌细胞的张力来调节脑血流。本研究采用共位活体光学成像和（11）C-ABP688 测定受体占有率，报告了在短暂的胡须刺激下，阻断体内约 80%的 mGluR5 并不影响短暂的血流动力学反应，而短暂的神经元活动则通过电压敏感染料成像来测量。我们的结果表明，在正常生理条件下，除了 mGluR5 的激活之外，还需要其他机制来触发初始的血流动力学反应。
