Tajemnice udaru mózgu: rola wapnia i magnezu w śmierci neuronów strefy półcienia

Abstrakt

Penumbra zone is localized on the border of ischaemic focus. Low cerebral blood flow allows the neurons to survive but it is insufficient for normal processes. Calcium ions play a significant role in the development of apoptosis within the neurons in penumbra. Intracellular calcium "swiches on" releasing cytochrom c from mitochondria - which is an important component of apoptosis. Extracellular calcium binds to the specific receptor localized on the cell membrane and activates antiapoptotic pathway which helps the cell to survive. Magnesium, in contrast to calcium ions, also excerts an antiapoptotic effect in the intracellular localization. Inhibition of glutamate (aminoacid which takes part in excitotoxicy) had brought the hope that magnesium could have been used in the stroke treatment. Unfortunately huge clinical trial with magnesium early administration in the acute ischemic stroke did not show the significant benefits of magnesium treatment. Future studies should be focused on recognition of molecular mechanism of magnesium and calcium ions acting in the excitotoxicy and apoptosis of the penumbra neurons.