Microglia swelling currents activation requires intracellular purines. (a) Time course of Iswell recorded with control pipette solution (2 mM Mg-ATP, n = 18; black) or with an ATP-free solution (n = 27; cyan; ***p = 0.001, two-way ANOVA, Holm-Sidak) under chronic hypotonic stimulation. (b) Time course of the swell-activated current evoked by acute application of hypotonic stimulus, in the presence of 2 mM Mg-ATP (black, n = 5) or without Mg-ATP (cyan, n = 6) in the intracellular solution. ***p = 0.001, two-way ANOVA, Holm-Sidak. Notice that after complete intracellular dialysis, ISwell is absent when ATP was omitted from pipette solution. (c) Bar chart representing swell-activated current amplitude (18 minutes after hypotonic stimulation; MP = + 50 mV) recorded with substitutions of Mg-ATP (2 mM) in the pipette solution. Each experimental set was compared with respective internal controls (recorded in the same experimental days with Mg-ATP in the pipette solution). CTR bar represents mean ISwell amplitude of all internal controls (2 mM Mg-ATP in the pipette solution, n = 48; blue bar). Na-ATP (2 mM, orange; n = 7 vs n = 10; p > 0.05, t-test), ATPγS (2 mM, violet; n = 11 vs n = 6; p > 0.05, t-test), Na-ADP (2 mM, pink; n = 12 vs n = 15; p > 0.05, t-test), adenosine (ADO, 2 mM, white; n = 10 vs n = 18; ***, p < 0.001, t-test) or with an ATP-free solution (gray; n = 23 vs n = 17; ***, p < 0.001, t-test).