Fig. 4

Ppt1 deficient (Ppt1^−/−) astrocytes exhibit changes in Ca²⁺ homeostasis. Ca²⁺ measurements were completed 48 h after seeding of wild type (WT) and Ppt1^−/− astrocytes under basal conditions to assess changes in Ca²⁺ homeostasis. Representative Ca²⁺ traces shown for WT (blue) and Ppt1^−/− (red) astrocytes (b-e). (a) Baseline Ca²⁺ levels measured with Fura2 dye (340/380 nm) were significantly higher in Ppt1^−/−astrocytes. (b) No statistically significant differences were detected between WT and Ppt1^−/− astrocytes in Ca²⁺ released from endoplasmic reticulum Ca²⁺ stores, mediated by 5 μM thapsigargin. c Lysosomal Ca²⁺ release, triggered by 10 μM nigericin was also not significantly altered in Ppt1^−/−astrocytes. d ATP (100 μM) mediated Ca²⁺ influx was significantly lower in Ppt1^−/−astrocytes than in their WT counterparts. e Store-operated Ca²⁺ entry, triggered by 5 μM thapsigargin followed by 1 mM CaCl₂, was significantly higher in Ppt1^−/−astrocytes than in WT astrocytes