The development of a new family of intracellular calcium probes

• Published in: Cell calcium (Edinburgh) Vol. 15; no. 2; pp. 190 - 198
• Main Authors: Iatridou, H., Foukaraki, E., Kuhn, M.A., Marcus, E.M., Haugland, R.P., Katerinopoulos, H.E.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier India Pvt Ltd 01.02.1994; Elsevier
• Subjects: Analytical biochemistry: general aspects, technics, instrumentation; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Calcium - analysis; Coumarins; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; Fluorescent Dyes - metabolism; Fundamental and applied biological sciences. Psychology; Mice; Analysis method; Calcium; Probe characterization; Spectral properties; Intracellular; Chemical synthesis; Quantitative analysis
• ISSN: 0143-4160; 1532-1991
• DOI: 10.1016/0143-4160(94)90058-2

Four new potential fluorescent probes for Ca 2+ using the coumarin moiety as a fluorophore have been synthesized and their spectral properties and binding affinities for Ca 2+ determined. The most promising derivative for intracellular use, BTC, exhibits an excitation wavelength shift from 462 nm to 401 nm on binding Ca 2+, with an emission wavelength of 530 nm. The quantum yield of this probe increases from 0.07 as the free indicator to 0.12 on binding Ca 2+. BTC, loaded as its tetraacetoxymethyl ester (AM ester) into mouse myeloma P3X cells, responded only when cytoplasmic Ca 2+ exceeded typical intracellular calcium concentrations. The dye, therefore, appears to be useful in excitatory cells or extracellular spaces with intracellular calcium concentrations high enough to saturate typical excitation ratio Ca 2+ indicators such as Fura-2.