ATP-binding cassette (ABC) proteins play key role in tissue defence by transporting metabolic waste and toxic chemicals out of the cells. Consequently, intact cell systems are required to study xenobiotic interactions with ATP-dependent transporters. The aim of the present study was to set up an intestinal precision-cut slice technique to study the interactions of ABC transporters with xenobiotics. Rat intestinal slices were incubated with verapamil, indomethacin and glibenclamide, and the ability of the above-mentioned drugs to inhibit the multidrug resistance glycoprotein (MDR) and/or multidrug-resistance-associated protein (MRP) was assessed by measuring the intracellular conversion of calcein-AM to fluorescent calcein. The ABC transporters' inhibitors caused a time-dependent florescence increase which reached the maximum value at 30 min. Verapamil and glibenclamide promoted a concentration-dependent intracellular accumulation of calcein (IC(50) 8.1×10(-6) M, 1.9×10(-4) M, respectively). The effect of glibenclamide was fully reversed by washing the slices, suggesting the reversible nature of calcein accumulation. These data suggest that the precision-cut intestinal slices are a reliable, simple and fast system to evaluate xenobiotic interactions with ABC transporters in rat and, hopefully, in human intestine.
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