Bozza Thomas, McGann John P, Mombaerts Peter, Wachowiak Matt
The Rockefeller University, New York, NY 10021, USA.
Neuron. 2004 Apr 8;42(1):9-21. doi: 10.1016/s0896-6273(04)00144-8.
Genetically encoded probes show great promise in permitting functional imaging of specified neuronal populations in the intact nervous system, yet their in vivo application has been limited. Here, we have targeted expression of synapto-pHluorin, a pH-sensitive protein that reports synaptic vesicle fusion, to olfactory sensory neurons in mouse. Synapto-pHluorin selectively labeled presynaptic terminals of sensory neurons in glomeruli of the olfactory bulb. Odorant stimulation evoked large-amplitude fluorescence increases that were localized to individual glomeruli in vivo, correlated with presynaptic calcium influx, graded with stimulus intensity, and stable over a period of days. Spatial patterns of odorant-activated glomeruli were distributed and did not change systematically with increasing carbon chain length, in contrast to the finely organized chemotopy that has been reported using other imaging methods. Targeted expression of synapto-pHluorin in mouse will permit the analysis of previously inaccessible neuronal populations and chronic imaging from genetically identified neurons in vivo.
基因编码探针在对完整神经系统中特定神经元群体进行功能成像方面显示出巨大潜力，但其体内应用一直受到限制。在此，我们将突触pH荧光蛋白（一种报告突触小泡融合的pH敏感蛋白）的表达靶向到小鼠的嗅觉感觉神经元。突触pH荧光蛋白选择性地标记了嗅球小球中感觉神经元的突触前终末。气味刺激在体内诱发了局限于单个小球的大幅度荧光增加，这与突触前钙内流相关，随刺激强度分级，并在数天内保持稳定。与使用其他成像方法报道的精细组织的化学拓扑结构相反，气味激活的小球的空间模式是分散的，并且不会随着碳链长度的增加而系统地改变。在小鼠中靶向表达突触pH荧光蛋白将有助于分析以前难以接近的神经元群体，并对体内基因鉴定的神经元进行长期成像。
