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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Brominated 7-hydroxycoumarin-4-ylmethyls : Photolabile protecting groups with biologically useful cross-sections for two photon photolysis TOSHIAKI FURUTA SAMUEL S.-H WANG
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Brominated 7-hydroxycoumarin-4-ylmethyls : Photolabile protecting groups with biologically useful cross-sections for two photon photolysis TOSHIAKI FURUTA SAMUEL S.-H WANG

机译：溴化的7-羟基香豆素-4-基甲基：具有光敏截面的光不稳定保护基，可用于两个光子的光解TOSHIAKI FURUTA SAMUEL S.-H WANG

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摘要

Photochemical release (uncaging) of bioac- tive messengers with three-dimensional spatial resolution in light-scattering media would be greatly facilitated if the photolysis could be powered by pairs of IR photons rather than the customary single UV photons. The quadratic dependence on light intensity would confine the photolysis to the focus point of the laser, and the longer wavelengths would be much less affected by scattering. However, previous caged messen- gers have had very small cross sections for two-photon excitation in the IR region. We now show that brominated 7-hydroxycoumarin-4-ylmethyl esters and carbamates effi- ciently release carboxylates and amines on photolysis, with onc- and two-photon cross sections up to one or two orders of magnitude better than previously available. These advantages are demonstrated on neurons in brain slices from rat cortex and hippocampus excited by glutamate uncaged from N(6- bromo- 7 -hydroxycoumarin -4 -ylmethoxycarbonyl)- L-gluta- mate (Bhc-glu). Conventional UV photolysis of Bhc-glu re- quires less than one-fifth the intensities needed by one of the best previous caged glutamates, r-(alpha-carboxy-2-nitrobenzyl)- L-glutamate (CNB-glu). Two-photon photolysis with raster- scanned femtosecond IR pulses gives the first three- dimensionally resolved maps of the glutamate scnsitivity of neurons in intact slices. Bhc-glu and analogs should allow more efficient and three-dimensionally localized uncaging and photocleavage, not only in cell biology and neurobiology but also in many technological applications.
机译：如果光解可以由成对的红外光子而非常规的单个紫外光子驱动，则将极大地促进在光散射介质中具有三维空间分辨率的生物活性信使的光化学释放（释放）。对光强度的二次依赖性将把光解作用限制在激光器的焦点上，更长的波长受散射的影响会小得多。但是，先前的笼状信使在红外区域的双光子激发具有非常小的横截面。我们现在显示，溴化的7-羟基香豆素-4-基甲基酯和氨基甲酸酯在光解时能有效地释放羧酸盐和胺类，其光子和两光子的横截面比以前更好，提高了一到两个数量级。这些优势在大鼠皮层和海马脑切片中的神经元上得到了证明，这些神经元被N（6-溴-7-羟基香豆素-4-基甲氧基羰基）-L-谷氨酸（Bhc-glu）释放的谷氨酸激发而来。 Bhc-glu的常规UV光解所需的强度不到以前最好的笼状谷氨酸盐之一，即r-（α-羧基-2-硝基苄基）-L-谷氨酸（CNB-glu）所需强度的五分之一。光栅扫描飞秒IR脉冲进行的两光子光解给出了完整切片中神经元的谷氨酸敏感性的第一个三维分辨图。 Bhc-glu及其类似物不仅在细胞生物学和神经生物学中，而且在许多技术应用中，都应允许进行更高效的三维局部解包和光切割。

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