Fig. 5

The ATP-induced current potentiation is downregulated in LPS-treated human microglia. a Time course of the mean current amplitude measured at −20 mV in control conditions, averaged from 5 cells (3 from #10 and 2 from #12) pre-treated with LPS (100 ng/ml for 48 h; LPS absent during the recording). Please note that LPS treatment completely abolished the ATP-induced current potentiation (p=0.027 when compared with control cells; n=5). b Time course of the mean current amplitude measured at −20 mV during the application of the selective K_Ca3.1 channel activator NS309 (500 nM, 20 s), averaged from 10 cells (2 from #5, 6 from #1, and 2 from #2). Voltage ramps applied every 2 s. Current amplitudes were normalized to the value averaged from the 5 currents preceding ATP administration. c Time course of the mean current amplitude during the application of NS309 on LPS-treated cells, averaged from 5 cells (#12). Please note that LPS treatment strongly reduced the NS309 effect. d Correlation plot linking the Ca²⁺-mediated ATP-induced current potentiation to the Ca²⁺-independent current potentiation induced by the selective K_Ca3.1 activator NS309. Data represent mean values ± standard error mean. Bidirectional errors are shown, sometimes not visible due to error amplitude smaller than symbol dimensions. Please note that LPS treatment reduces both types of modulation, indicating a reduction in the functional expression of K_Ca3.1 as the cause of the lack of Ca²⁺-mediated current potentiation observed in LPS-treated cells