[Neuroprotective effect of oestrogen on the central nervous system]

It has been demonstrated that some regions of the brain are endowed in oestrogen receptors alpha and beta. Moreover, some neuroprotectants were found to be differently effective in both sexes. Such findings have naturally aroused interest in possible neuroprotective effects of female sex hormones. Today is apparent that the brain is a target organ for oestrogen and both neuronal activity and regional cerebral blood flow can be modulated by this hormone. By stimulating formation of new synaptic connections, oestrogen can also increase brain plasticity, cognitive functions and memory. It has been demonstrated that oestrogen increases regional and global cerebral blood flow by decreasing cerebral vascular impedance and by favourable modification of rheological properties of blood (attenuation of platelet aggregation and adhesion, diminution of leukocyte's contact with the vascular wall, etc.). Oestrogen also mitigates inflammatory and immunological reactions and protects vascular endothelium by reducing apoptosis of the endothelial cells. It also stimulates secretion of different grow factors like BDNF, FGF, NGF, or IGF. Foremost, by its complex interactions with different harmful biochemical reactions occuring during brain ischemia, oestrogen in a great degree prevents formation of free oxygen radicals. Taking the above into consideration and remembering neuroprotective role of endogenous oestrogen, some authors suggest the use of exogenous oestrogen as a therapeutical neuroprotector.