Glutamate-induced increase in [Ca2+]
in astrocytoma cells. A: Quantification of changes in [Ca2+]i as measured microfluorimetrically in Fura-2 loaded cells. Typical individual responses observed after addition of 300 μM glutamate are shown. In a large number of cells, glutamate elicited single Ca2+ spike while a second spike can be observed in 10-20% of the cells analyzed. B: Glutamate induced a concentration-dependent increase in [Ca2+]i. Data are mean ± SEM of 4 independent experiments.