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Calibration of intracellular ion probes
Author(s) -
Rana Priyanka S.,
Lu Yong,
Yurinskaya Valentina E.,
Vereninov Alexey A.,
Model Michael A.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.624.37
Subject(s) - nigericin , intracellular , valinomycin , ion , calibration , biophysics , chemistry , fluorescence , extracellular , nernst equation , ouabain , membrane permeability , membrane , membrane potential , analytical chemistry (journal) , biological system , physics , biochemistry , chromatography , biology , sodium , optics , organic chemistry , electrode , quantum mechanics
The development of ion‐sensitive fluorescent probes enables the measurement of intracellular concentrations of ions (such as H + , K + , Na + , Ca 2+ , etc.) in a non‐invasive manner. One major complication with their use arises from their unpredictable behavior inside the cell, which makes it necessary to calibrate them in situ . Calibration implies creating known intracellular ion concentrations C i (for example, making them equal to extracellular concentrations C e ) and relating them to the measured fluorescent signal. The question is how to ensure C i = C e ? Despite the long history of use of intracellular ion probes, the answer to this question is hard to find in the literature. In fact, many of the published calibration protocols clearly fail to achieve the desired goal. We therefore undertook a theoretical and experimental study of this question using K + as an example. The general recipe for ion equilibration requires two conditions: (1) cell membrane potential should be destroyed; (2) membrane permeability for both K + and Na + should be significantly increased. Our results indicate that a combination of gramicidin, valinomycin, nigericin and ouabain is most suitable for achieving equalization of K + across the membrane. Calibration curves obtained with suboptimal choice of ionophores leads to erroneous potassium measurements. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .