In developing the methods for our studies we have used an enzymatic approach with application of Saccharomyces cerevisiae exopolyphosphatase X (scPPX1). ScPPX1 is an effective polyphosphatase that possesses high substrate specificity and hydrolyses orthophosphates from polyP chains of varied lengths, but not from ATP, pyrophosphate and trimetaphosphate [35]. In order to detect a possible effect of polyP on TRPM8 we conducted a number of experiments with application, or expression, of scPPX1 in HEK-293 cells. In whole-cell patch clamp experiments, dialysis of purified scPPX1 through the patch pipette into cells transiently transfected with TRPM8 significantly inhibited menthol-induced
currents in a time period of 3–5 min of treatment with scPPX1 (Fig. 1A–C). The concentration of scPPX1 in the pipette solution (2.3 μg/ml) was sufficient to observe inhibition within the tested time.