Fig. 3.

Pharmacological analysis of spontaneous [Ca²⁺]_i transients in hippocampal astrocytes. A, Histograms illustrating the percentage of hippocampal P2–P6 GFAP/GFP-positive astrocytes showing spontaneous Ca²⁺ activity after administration of a range of neurotransmitter receptor antagonists, TTX, and blockers of Ca²⁺ mobilization. Significant reductions are observed after EGTA, Co²⁺, and thapsigargin treatments (*p < 0.05; **p < 0.01; ***p < 0.001). Each experimental condition was performed in at least three slices. Data are expressed as percentages of control values (mean ± SEM). B, Representative plots of [Ca²⁺]_ioscillations recorded in the same GFAP/GFP-positive astrocyte from a P6 mouse perfused with normal ACSF (basal and washout), Ca²⁺-free ACSF (2 mm EGTA, 0 mm [Ca²⁺]_o), and thapsigargin (2 μm). C, D, [Ca²⁺]_i oscillations recorded in P5 GFAP/GFP-positive astrocytes are abolished after perfusion of Ca²⁺-free ACSF. Addition of t-ACPD and 4-CmC (arrows) to nominally Ca²⁺-free ACSF caused a transient and a progressive increase in [Ca²⁺]_i, respectively. Abbreviations are defined in Materials and Methods.