Figure 6: Increasing ADP availability by apyrase application amplifies astrocytic hyperactivity and calcium waves.

(a) Augmenting the hydrolysis of ATP to ADP, while minimizing ADP degradation, using the ectonuleotidase apyrase significantly increased the frequency of astrocytic transients in all active astrocytes (P<0.05, Mann–Whitney test; n=126 astrocytes from n=3 mice). (b) Apyrase significantly increased the fraction of hyperactive astrocytes and decreased the fraction of inactive astrocytes in APPPS1 mice (P<0.05, χ2-test). (c) Apyrase significantly increase the frequency of astrocytic calcium waves in APPPS1 mice (P<0.05, Mann–Whitney test). (d,e) There was a nonsignificant trend towards a higher velocity of calcium waves after apyrase treatment. No significant difference was observed in the maximal distance calcium waves propagated within the imaging plane (P>0.05, Mann–Whitney test for both).