Fig. 3

ATP evokes increases in intracellular calcium in both adherent and neurosphere GL261 cells. a Pseudocolored images represent intracellular calcium levels in adherent (AC) or neurosphere (NS) GL261 cells under basal conditions and after exposure to 200 μM ATP (200X magnification). Pseudocolor scale bars depict the fura-2 signal ratio, with warmer colors indicating increased intracellular calcium concentrations. b Mean percentage of AC (n = 11) or NS (n = 12) GL261 cells that respond to 200 μM ATP. Bars indicate standard error of the mean. No significant difference was detected between the two groups at a threshold of p < 0.05 (p = 0.09, Student’s t-test)