Figure 2.

Intracellular Ca²⁺ rise in glial cells and fEPSP depression induced by NMDA application. A, Representative single experiment (top panel; n = 1 slice) and group data (bottom panel; n = 7 slices) showing changes in fEPSP amplitude expressed as percentage of baseline before, during, and after NMDA bath application (25 μm; 3 min) (bar) in paired control experiments and in the presence of d-AP5 (50 μm). Bath application of NMDA induced a reduction of fEPSP that was prevented by 50 μm d-AP5 (n = 7 slices; Student’s paired t test; p < 0.001). Top insets show examples of fEPSPs before (1) and during (2) synaptic depression in control and in the presence of d-AP5 (3) (calibration: 0.5 mV, 40 ms). B, Relative increase (mean ± SEM) in fluorescence for glial cells in the individual slice shown in A (top panel; n = 6 cells) and for all slices (bottom panel; n = 54 cells, 7 slices) before, during, and after NMDA bath application in control (gray) and in the presence of d-AP5 (black). NMDA elicited glial Ca²⁺ responses that were prevented by 50 μm d-AP5 (Student’s paired t test; p < 0.001). Responses obtained in control and in the presence of d-AP5 were obtained from the same slices as in A. Top insets show pseudocolor (blue-red scale) confocal images of a glial cell loaded with fluo3-AM before (1) and during (2) NMDA-induced elevation of Ca²⁺ in control, and in the presence of d-AP5 (3). Scale bar, 10 μm. Ctrl, Control; resp., response.