Hippocampal neurons pretreated with estradiol and then exposed to excitotoxic glutamate respond with an attenuated rise in intracellular calcium and increased survival relative to untreated neurons [103,108]. Such attenuation occurs without an alteration in the number of neurons that responded to glutamate [108]. This estradiol-inducible attenuation of the rise in bulk free intracellular calcium induced by excitotoxic glutamate is dependent upon mitochondrial sequestration of calcium. Mitochondrial inhibition by (1) a combination of rotenone, to inhibit the respiratory chain at complex I, and oligomycin, to inhibit mitochondrial ATP synthase, or (2) antimycin, to inhibit the respiratory chain at complex III, completely depolarize in situ mitochondria, effectively blocking mitochondrial calcium accumulation [24,148] and block the estradiol-induced attenuation of the rise in bulk free intracellular calcium (Fig. 2) [103].