FIGURE 1.

Astrocyte-specific expression of venus tagged IP₃ 5′phosphatase (VIPP) attenuates Ca²⁺ signaling in hippocampal CA1 astrocytes. (A) Cartoon depicting the GFAP promoter driving the expression of VIPP and β-gal. (B,C) Top view confocal images (20× 0.7NA objective) of hippocampal CA1-region showing VIPP expression and CA1 neurons (NeuN) and astrocytes (GFAP). (D–H) High magnification single confocal planes (60× 1.4NA objective) showing VIPP colocalizes with GFAP (D), but not with NG2 (E), Olig1 (F) Iba1 (G) or NeuN (H). (I) Quantification of D–H. n = 6 animals for each staining. (J,K) Astrocytic Ca²⁺ responses in response to 100 μM ATP (J,K), five theta trains (L,M) or 100 Hz, 1 s tetanic stimulation (N,O) are significantly attenuated by expression of VIPP (green). Quantitation (K,M,O) is shown as the integral of ΔF/F₀ signal for 2 min after ATP application (t-test, ^∗p < 0.0016 in K; p < 0.025 in M; p < 0.006 in O), for 3 min after theta burst stimulation and 3 min following tetanic stimulation of the Schaffer collaterals. Number of tested cells and tested slices (in parenthesis) are indicated.