TY - JOUR T1 - Differential Mechanisms of Neuroprotection by 17 β-Estradiol in Apoptotic versus Necrotic Neurodegeneration JF - The Journal of Neuroscience JO - J. Neurosci. SP - 2600 LP - 2609 DO - 10.1523/JNEUROSCI.21-08-02600.2001 VL - 21 IS - 8 AU - Christoph Harms AU - Marion Lautenschlager AU - Alexandra Bergk AU - Juri Katchanov AU - Dorette Freyer AU - Krisztian Kapinya AU - Ulrike Herwig AU - Dirk Megow AU - Ulrich Dirnagl AU - Joerg R. Weber AU - Heide Hörtnagl Y1 - 2001/04/15 UR - http://www.jneurosci.org/content/21/8/2600.abstract N2 - The major goal of this study was to compare mechanisms of the neuroprotective potential of 17 β-estradiol in two models for oxidative stress-independent apoptotic neuronal cell death with that in necrotic neuronal cell death in primary neuronal cultures derived from rat hippocampus, septum, or cortex. Neuronal apoptosis was induced either by staurosporine or ethylcholine aziridinium (AF64A), as models for necrotic cell death glutamate exposure or oxygen–glucose deprivation (OGD) were applied. Long-term (20 hr) pretreatment (0.1 μm 17 β-estradiol) was neuroprotective in apoptotic neuronal cell death induced by AF64A (40 μm) only in hippocampal and septal neuronal cultures and not in cortical cultures. The neuroprotective effect was blocked by the estrogen antagonists ICI 182,780 and tamoxifen and the phosphatidylinositol 3-kinase (PI3-K) inhibitor LY294002. In glutamate and OGD-induced neuronal damage, long-term pretreatment was not effective. In contrast, short-term (1 hr) pretreatment with 17 β-estradiol in the dose range of 0.5–1.0 μm significantly reduced the release of lactate dehydrogenase and improved morphology of cortical cultures exposed to glutamate or OGD but was not effective in the AF64A model. Staurosporine-induced apoptosis was not prevented by either long- or short-term pretreatment. The strong expression of the estrogen receptor-α and the modulation of Bcl proteins by 17 β-estradiol in hippocampal and septal but not in cortical cultures indicates that the prevention of apoptotic, but not of necrotic, neuronal cell death by 17 β-estradiol possibly depends on the induction of Bcl proteins and the density of estrogen receptor-α. ER -