FLUO 4 AM

Other Names Fluo 3 pentaacetoxymethyl ester Fluo 

Absorption (Xmax) 464 nm Emission (Amax) Fluorescence is very weak Synthesis Synthetic methods  

Staining Applications Calcium ions cells sperms neurons  

Biological Applications Calcium indicator detecting leukocyte tumor cells identifying taste modulators treating pain  

Industrial Applications Light emitting diodes Safety/Toxicity Cellular toxicity phototoxicity  

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FIGURE 7.5 7,8-BPQ increases intracellular Ca2+ in murine spleen cells (A) and in both B and T cells (B). Single cell suspensions were prepared from murine spleens. Splenocytes were loaded with Fluo-3/AM dye for one hour and then treated with 7,8-BPQ, 1,6-BPQ, 3,6-BPQ, or DMSO (control). Surface-marker-defined T cells and B cells were treated with 7,8-BPQ or DMSO. Following treatment, the immediate intracellular Ca2+ response was continuously monitored for 15 minutes. Results are shown as the change in Mean Channel Fluorescence SEM. The numbers shown in this figure were the averages of triplicate determinants. Adapted from Gao et al., 2005. 

Figure 6.11. Intracellular Ca2+ levels during neutrophil activation with fMet-Leu-Phe. Neutrophil suspensions were loaded with Fluo-3 AM for 15 min. This molecule is membrane permeable but cleaved by intracellular esterase activity to yield the polar molecule Fluo-3, which is thus trapped within the cell. The neutrophils were then suspended in buffer that was devoid of Ca2+, and treated as shown. In (a), 1 mM Ca2+ and 1 /tM fMet-Leu-Phe were added to the suspension, as indicated by the arrows. In (b), 1 mM EGTA and 1 pM fMet-Leu-Phe were added as shown. Thus, in (a), the change in intracellular Ca2+ is due to mobilisation of intracellular Ca2+ stores and the influx of extracellular Ca2+, whereas in (b), the Ca2+ rise is due solely to release of Ca2+ from intracellular stores.

Cells are loaded with a Ca -sensitive fluorescent dye (Fluo-3 AM, Ca-Green AM). 

Calcein, fura-2, BTC, various der. of Calcium Green, fluo-3 AM and fluo-4 AM and some of their dextran conjugates... 

A product that is widely used, and one that has also grown in importance since the advent of high throughput screening methods, is the AM (acetoxymethyl) ester of the fluoran derivative, Fluo-3 (3.67). This product, Fluo-3AM, does not itself bind Ca but is readily hydrolysed to Fluo-3 by endogenous esterases once the dye is in the cells. 

Fig. 5 Venn-diagram for selected compounds interacting with the key MDR-related ABC transporters. Fluorescent Compounds for the functional detection of multi drug resistance. Abbreviations CA-AM calcein AM, FL-3-AM fluo-3AM, Pot. Dyes potentiomeric dyes, RFI123 rhodaminel23, HST fioechst dye No. 33342, GS-N-PM N-Pyrenemaleimide glutathione conjugate, BOD-VER BODIPY verapamil, BOD-PRAS BODIPY prazosin, MX mitoxantrone, LYS LysoTracker dye. (Reproduced from [4])...

Fluo-3 (1) is a Ca -responsive fluorescein sensor based on the PET mechanism. The fluorescence response of Fluo-3 to Cd " is the same as that observed with Ca " or 7x3 moreover, neither of these metals influences the Cd -induced Huo-3 fluorescence due to the large difference in their binding constants. In practical applications, the probe is loaded into rat thymocytes as the membrane-permeable acetoxymethyl (AM) ester form. Subsequent flow cytometric analysis is characterized by increased intensity of the Fluo-3 fluorescence when the cells are exposed to Cd ", corresponding to the formation of the Cd -Huo-3 complex in the cells [37,38]. 

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