Fig. 4
The ATP-induced current potentiation is due to Ca2+-dependent K+ and Cl− conductances. a Time course of the mean current amplitude measured at −20 mV in control conditions, averaged from 11 cells (6 from #3 and 5 from #9; same data of Fig. 3b). Voltage ramps were applied every 2 s. Current amplitudes were normalized to the value averaged from the 5 currents preceding ATP administration. b Time course of the mean current amplitude measured at −20 mV in the presence of TRAM-34 (1 μM), averaged from 10 cells (#3). c Time course of the mean current amplitude measured at −20 mV in the absence of external Cl− and in the presence of TRAM-34 (1 μM), averaged from 7 cells (#11). d Histogram representing the mean current density measured at −20 mV immediately before (gray) and after (white) the ATP administration, in different experimental conditions, as indicated. The numbers of recorded cells for control (left bars), only TRAM-34, and Cl−-free + TRAM-34 (right bars) were 13 (6 from #3, 5 from #9, and 2 from #12), 10 (#3), and 7 (#11), respectively. Two asterisks denote significantly higher than before ATP, p<0.001. *p=0.031. a Mean peak value in control condition is significantly higher than in Cl−-free + TRAM-34 (p=0.016). b Mean peak value in TRAM-34 is significantly higher than in Cl−-free + TRAM-34 (p=0.040)