Figure 1.

Dopamine‐triggered Ca²⁺ responses in CA1 stratum radiatum astroglia. A: Example of a patched (PAC) and GJC astroglia (Alexa 594, λ_x ^2P = 800 nm). B: Traces, characteristic Ca²⁺‐dependent fluorescence (Fluo‐4 channel) monitored in GJC astroglia (soma) during application of dopamine (100 µM, orange bar); blue arrows, clear negative defections of Ca²⁺ signal indicating decreases in [Ca²⁺]. C: Example of astroglia bulk‐labeled with sulforhodamine 101 (SR101) and Fluo‐4 AM (SR101 channel, λ _x ^2P = 800 nm). D: Traces, characteristic Ca²⁺‐dependent fluorescence (Fluo‐4 channel) monitored in bulk‐labeled astroglia (soma) during paired bath application of dopamine (100 µM, grey bars); image panels, illustration of Fluo‐4 channel recording of individual astroglia corresponding to experimental epochs 1‐5, as in the traces. E: Average time course (mean ± SEM) of Ca²⁺‐dependent fluorescence (Fluo‐4 channel) in GJC (open circles, n = 16) and Fluo‐4 AM bulk‐labeled astroglia (grey circles, n = 14), as indicated, in response to application of dopamine (100 µM, orange bar; single‐stimulus DA responses only). F: Dose dependence of dopamine‐induced astroglial Ca²⁺ response (ΔF/F, mean ± SEM amplitude) in bulk labeled and GJC astroglia, as indicated; digits inside columns, sample size; **P < 0.01, ***P < 0.005. G: Average amplitude (ΔF/F, mean ± SEM) of Ca²⁺ response to dopamine (application as in B) in bulk‐loaded astroglia in the presence of TTX (1 μM; responses to drug application alone, before DA application are shown in grey here), non‐specific mGluR blocker MCPG (200 µM), D1/5 receptor blocker SCH23390 (20 μM) and D2/3 receptor blocker sulpiride (50 μM) (SCH+Sulp), and monoamine oxidase B (MAOb) inhibitor selegiline (20 μM, Sg), as indicated; digits inside columns, sample size. *P < 0.05. H: Average amplitude (ΔF/F, mean ± SEM) of Ca²⁺ response in Fluo‐4 AM bulk‐loaded astroglia to paired‐application of dopamine (as in D), with the drug applied before the second stimulus: control, selegiline (20 μM), and IP3 receptor blocker 2‐APB (100 µM); digits inside columns, sample size; **P < 0.01, ***P < 0.005. I: Average amplitude (ΔF/F, mean ± SEM) of Ca²⁺ response in GJC astroglia to dopamine (100 µM, as in A‐B), in the presence of a drug cocktail containing TTX (1 μM), mGluR5 blocker MPEP (1 μM), mGluR5 blocker LY367385 (100 μM), mGluR2/3 blocker LY341495 (500 nM) and GABAB receptor blocker CGP (1 μM); a selective purinergic P2X antagonist PPADS (100 µM), D1/5 receptor blocker SCH23390 (20 μM) and D2/3 receptor blocker sulpiride (50 μM) (SCH+Sulp), sulpiride only (50 µM), and SCH23390 only (10 µM); *P < 0.05; **P < 0.01 (note two‐scale ordinate). [Color figure can be viewed at wileyonlinelibrary.com]