Figure 3.

Normal calcium handling capacity in S100B-null astrocytes. Transillumination (A) and epifluorescence (B) images obtained from the CA1 region of a hippocampal slice loaded with a fluorescent calcium indicator. Arrowhead and asterisk in A indicate stimulation and recording electrodes, respectively. Rectangles (30 μm × 45 μm) separated by 40–50-μm intervals along the Schaffer collateral pathway indicate the areas measured. Note that pyramidal cell bodies in B are not labeled. (Scale bar, 50 μm.) (C) Relative fluorescent change evoked by tetanic stimulation (two 1-s, 100-Hz trains at 5-s intervals, indicated by solid bars). Traces were obtained from areas as indicated in A. [Scale bars, 1 s (horizontal) and 5% change in fluorescence (vertical).] (D) Same stimulation as in C before, during, and after superfusion of D-APV (50 μM). (E and F) Quantitative analysis of tetanus-induced calcium signals (mean ± SE). Amplitude of calcium transients evoked by the first and the second 100-Hz train are shown in E and F, respectively. There were no differences between wild-type (n = 12 slices/5 mice) and mutant (n = 12 slices/5 mice) mouse slices in all three areas. s.rad., stratum radiatum; s.lac.mol., stratum lacunosum molecular; s.or., stratum oriens; pyr., CA1 pyramidal cell layer.