FIGURE 4.

Adenosine kinase mediates the NAD⁺-induced increases in the intracellular levels of ATP, ADP, and AMP of BV2 microglia under basal conditions. (A) NAD⁺ treatment dose-dependently increased the intracellular adenosine level of the cells. (B) 500 μM NAD⁺ time-dependently increased the intracellular adenosine level of BV2 cells. (C) Treatment of the cells with 5 μM 5-ITU blocked the NAD⁺-induced increases in the intracellular ATP levels of the cells. (D) Treatment of the cells with 5 μM 5-ITU blocked the NAD⁺- induced increases in the intracellular ADP levels of the cells. (E) Treatment of the cells with 5 μM 5-ITU blocked the NAD⁺-induced increases in the intracellular AMP levels of the cells. The cells were co-treated with 5 μM 5-ITU and NAD⁺ for 3 h before the assays were conducted. N = 16. The data were pooled from four independent experiments. ^∗∗∗P < 0.001.