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Selective Zinc Sensor Molecules With Various Affinities for Zn2+, Revealing Dynamics and Regional Distribution of Synaptically Released Zn2+ in Hippocampal Slices

Kensuke Komatsu, Kazuya Kikuchi, Hirotatsu Kojima, Yasuteru Urano, Tetsuo Nagano

J Am Chem Soc. 2005 Jul 27;127(29):10197-204.

PMID: 16028930

Abstract:

We have developed a series of fluorescent Zn(2+) sensor molecules with distinct affinities for Zn(2+), because biological Zn(2+) concentrations vary over a wide range from sub-nanomolar to millimolar. The new sensors have K(d) values in the range of 10(-8)-10(-4) M, compared with 2.7 nM for ZnAF-2. They do not fluoresce in the presence of other biologically important metal ions such as calcium or magnesium, and they can detect Zn(2+) within 100 ms. In cultured cells, the fluorescence intensity of ZnAF-2 was saturated at low Zn(2+) concentration, while that of ZnAF-3 (K(d) = 0.79 muM) was not saturated even at relatively high Zn(2+) concentrations. In hippocampal slices, we measured synaptic release of Zn(2+) in response to high-potassium-induced depolarization. ZnAF-2 showed similar levels of fluorescence increase in dentate gyrus (DG), CA3 and CA1, which were indistinguishable. However, ZnAF-3 showed a fluorescence increase only in DG. Thus, by using a combination of sensor molecules, it was demonstrated for the first time that a higher Zn(2+) concentration is released in DG than in CA3 or CA1 and that we can easily visualize Zn(2+) concentration over a wide range. We believe that the use of various combinations of ZnAF family members will offer unprecedented versatility for fluorescence-microscopic imaging of Zn(2+) in biological applications.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP321859114 ZnAF-2 ZnAF-2 321859-11-4 Price
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