Reinert Kenneth C, Gao Wangcai, Chen Gang, Ebner Timothy J
Department of Neuroscience, University of Minnesota, 421 Lions Research Building, Minneapolis, MN 55455, USA.
J Neurosci Res. 2007 Nov 15;85(15):3221-32. doi: 10.1002/jnr.21348.
Autofluorescence optical imaging is rapidly becoming a widely used tool for mapping activity in the central nervous system function in vivo and investigating the coupling among neurons, glia, and metabolism. This paper provides a brief review of autofluorescence and of our recent work using flavoprotein imaging in the cerebellar cortex. Stimulation of the parallel fibers evokes an intrinsic fluorescence signal that is tightly coupled to neuronal activation and primarily generated postsynaptically. The signal originates from mitochondrial flavoproteins. The signal is biphasic, with the initial increase in fluorescence (light phase) resulting from the oxidation of flavoproteins and the subsequent decrease (dark phase) from the reduction of flavoproteins. The light phase is primarily neuronal, and the dark phase is primarily glial. Exploiting the spatial properties of molecular layer inhibition in the cerebellar cortex, we show that flavoprotein autofluorescence can monitor both excitatory and inhibitory activity in the cerebellar cortex. Furthermore, flavoprotein autofluorescence has revealed that molecular layer inhibition is organized into parasagittal domains that differentially modulate the spatial pattern of cerebellar cortical activity. The reduction in flavoprotein autofluorescence occurring in the inhibitory bands most likely reflects a decrease in intracellular Ca(2+) in the neurons inhibited by the molecular layer interneurons. Therefore, flavoprotein autofluorescence imaging is providing new insights into cerebellar cortical function and neurometabolic coupling.
自发荧光光学成像正迅速成为一种广泛应用的工具，用于在体内绘制中枢神经系统功能活动图谱，并研究神经元、神经胶质细胞和新陈代谢之间的耦合关系。本文简要回顾了自发荧光以及我们最近在小脑皮质中使用黄素蛋白成像的工作。平行纤维的刺激会引发一种内在荧光信号，该信号与神经元激活紧密耦合，主要在突触后产生。该信号源自线粒体黄素蛋白。该信号是双相的，荧光的初始增加（亮相）是由黄素蛋白的氧化引起的，随后的减少（暗相）是由黄素蛋白的还原引起的。亮相主要是神经元性的，暗相主要是神经胶质细胞性的。利用小脑皮质分子层抑制的空间特性，我们表明黄素蛋白自发荧光可以监测小脑皮质中的兴奋性和抑制性活动。此外，黄素蛋白自发荧光揭示了分子层抑制被组织成矢状旁区，这些区域对小脑皮质活动的空间模式进行差异性调节。在抑制带中发生的黄素蛋白自发荧光的降低很可能反映了被分子层中间神经元抑制的神经元内细胞内Ca(2+)的减少。因此，黄素蛋白自发荧光成像为小脑皮质功能和神经代谢耦合提供了新的见解。
