Effects of oxidative challenge and calcium on ATP-levels in neuronal cells.

Background: Neurocellular overload with hydrogen peroxide (H2O2) induces oxidative stress and may initiate a cascade of intracellular toxic events leading to energy failure, increased lipid peroxidation and subsequently cell death. Studies suggest that hippocampal neurons may be more vulnerable to oxidative stress than cortical cells pointing to a differential vulnerability of neuronal cells. Since disturbed ATP- and calcium (Ca2+)-metabolism may be involved in this process, we here evaluated the effects of H2O2-induced oxidative stress and the involvement of Ca2+-regulation on neuronal energy metabolism.

2-OH-estradiol, an endogenous hormone with neuroprotective functions.

We compared the neuroprotective effects of the catecholestrogen 2-hydroxy-estradiol (2-OH-E(2)) to the actions of 17-beta-estradiol (E(2)), since catecholestrogens have been clinically implicated in the pathophysiology of major depression and other psychiatric diseases. Using the hippocampal HT22 cell line as a well-established in vitro model system, we here show that the extent of the neuroprotective effects of 2-OH-E(2) was significantly increased compared to the physiological estrogen E(2) at equimolar concentrations after a toxic challenge with hydrogen peroxide. Statistically significant effects of neuroprotection as measured by survival of HT22 cells were detectable at concentrations of 1 and 10 microM of 2-OH-E(2) or E(2).