Figure 1. Glycogenolysis is required for the increase of ATP release from well differentiated astrocyte cultures induced by the addition of glutamate to a final concentration of 100 μM, adenosine to a final concentration of 100 μM or elevation of the extracellular K⁺ concentration by 45 mM.

The presence of any of these stimuli during incubation for 60 min in glucose-containing (7.5 mM) DMEM supplemented with the ecto-ATPase inhibitor ARL67156 increased the content of ATP, measured as RLU by a luciferin/luciferase technique. This increase was almost abolished in the additional presence of the glycogenolysis inhibitor (DAB). Results are the averages of RLU values from three to five individual cultures. S.E.M. values are indicated by vertical bars. *Statistically significant (P<0.05) difference from all other groups, but not from each other.