ATP-evoked biphasic currents did not result from Panx1 activation. A, PCR results for wild-type (+/+) mice, heterozygote mice (+/−), and Panx1 KO mice (−/−). B, Voltage-current relationship of currents recorded in microglia obtained from the SC of E13.5 Panx1−/− mouse embryos. A voltage ramp protocol (−100 mV +100 mV; 2 s) was used to investigate voltage-activated currents. C1, C2, Effect of high concentrations of the hemichannel blockers DIDS and CBX on ATP-evoked currents (3 mm ATP; Vh = −60 mV) in CXCR1eGFP mice. C3, 100 μm DIDS significantly (p < 0.01) inhibits 28.3 ± 2.9% (N = 11) of ATP responses while 100 μm CBX had no significant effect (p > 0.1) (9.9 ± 6.6% increase; N = 7). The percentage change in response amplitude observed during the application of the blockers was compensated according to the averaged decrease (rundown: 6.8%) in the corresponding responses observed on different cells in the absence of the blockers (Normal [Ca2+]o and [Mg2+]o ACSF: see Materials and Methods and Results). Error bars indicate SEM. D, Currents evoked by 3 mm ATP on microglia recorded from the SC of E13.5 Panx1 −/− mouse embryos. Note that ATP application evoked a biphasic current as observed in CX3CR1eGFP and in P2X7+/− mouse embryos (Figs. 3, 6).