Figure 1

Concentration–response curves for the ability of adenosine, ATP, ADP, BzATP, UDP or UTP to stimulate Ca²⁺ influx to cytoplasm of the CHO cells. Cytoplasmic Ca²⁺ influx, [Ca²⁺]_cyt, measurements were monitored through changes of the Fluo-4 fluorescence intensity in real time using the Flex Station 3 microplate reader system. CHO-K1 (●-●) and CHO-745 (□-□) cells were seeded onto black 96-well plates (10⁴ cells/well). Then, the cells were incubated with Fluo-4 for 1 h at 37 °C. The samples were monitored for 200 s, and the amplitude of the basal and maximum fluorescence value, after agonist stimulus with adenosine (a), ATP (b), ADP (c), BzATP (d), UDP (e) or UTP (f) to obtain the corresponding concentration–response curves. The data represent the mean±S.E.M. (N=6).