Tóth A, Ivanics T, Ruttner Z, Slaaf D W, Reneman R S, Ligeti L
Second Department of Physiology, Semmelweis Medical University, H-1082 Budapest, Hungary.
Am J Physiol. 1998 Nov;275(5):H1652-62. doi: 10.1152/ajpheart.1998.275.5.H1652.
Intracellular free Ca2+ concentration ([Ca2+]i) plays an essential role in physiological regulatory processes and common pathological conditions. Better understanding of these phenomena is still hampered by problems encountered in the quantitative assessment of [Ca2+]i changes, especially in blood-perfused organs. This study demonstrates that the ratiometric fluorescence technique can be adapted for quantitative in vivo [Ca2+]i determinations. The rat spinotrapezius muscle was topically loaded with indo 1-AM and imaged by a cooled digital camera. Ratio images were calculated in small regions (100 micrometers x 100 micrometers) practically devoid of large vessels in the resting state, after 30 min of ischemia, 20 min of reperfusion, or ionomycin or manganate treatments. When we assumed an average [Ca2+]i of 100 nM in the resting blood-perfused muscle, ischemia increased [Ca2+]i to approximately 200 nM. During reperfusion [Ca2+]i decreased to approximately 140 nM. Ionomycin induced an increase in [Ca2+]i to well above 750 nM. Manganate reduced Ca2+-dependent fluorescence to virtually zero. Our main conclusion is that changes in [Ca2+]i can be monitored and quantitatively determined in vivo.
细胞内游离钙离子浓度（[Ca2+]i）在生理调节过程和常见病理状况中发挥着至关重要的作用。然而，对[Ca2+]i变化进行定量评估时遇到的问题，尤其是在血液灌注器官中，仍然阻碍着我们对这些现象的深入理解。本研究表明，比率荧光技术可用于体内[Ca2+]i的定量测定。将大鼠斜方肌局部加载indo 1-AM，并通过冷却数码相机进行成像。在静息状态下、缺血30分钟后、再灌注20分钟后，或经离子霉素或锰处理后，在几乎没有大血管的小区域（100微米×100微米）计算比率图像。当我们假设静息血液灌注肌肉中的平均[Ca2+]i为100 nM时，缺血使[Ca2+]i增加至约200 nM。再灌注期间，[Ca2+]i降至约140 nM。离子霉素使[Ca2+]i增加至远高于750 nM。锰将钙依赖性荧光降低至几乎为零。我们的主要结论是，[Ca2+]i的变化可在体内进行监测和定量测定。
