Artikel
After ventricular hemorrhage the ATP-sensitive PY2-receptor induces a Ca2+-rise in the cytosol resulting in necrosis but not apoptosis in human astrocytes
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Veröffentlicht: | 20. Mai 2009 |
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Objective: Ca2+-is a cofactor of many cellular processes including apoptosis and necrosis. This study’s hypothesis was that bloody CSF from patients after intraventricular hemorrhage may cause a Ca2+-rise which induces apoptosis or necrosis in an in-vitro model of human cerebral astrocytes.
Methods: Human astrocytes were incubated with CSF from patients with intraventicular hemorrhage. In control experiments, native CSF was used. Single cell cytosolic Ca2+-concentrations were measured by fura-2 microfluometry. Three blockers were used: Nimodipine, APB and suramine that blocks the L-type Ca2+-channel, the membrane and endoplasmic reticulum Ca2+-channels; and the ATP-sensitive PY2-rezeptor, respectively. Apoptosis and necrosis were evaluated by staining with Hoechst-3342 and propidium iodide.
Results: Incubation of astrocytes with bloody-CSF provoked a cytosolic Ca2+-rise a typical pattern: after an initial peak, Ca2+ concentration almost returned to baseline but then increased slowly but long lasting over the observation period of 60 min. The Ca2+-rise was significantly blocked by APB and suramin. Nimodipine had no influence on the cytosolic Ca2+-concentration. Incubation of the astrocytes with bloody-CSF induced necrosis but not apoptosis. The blockade of the Ca2+-rise by APB or Suramin reduced necrosis significantly. Nimodipine did not prevent astrocytic necrosis.
Conclusions: Bloody CSF induces an Ca2+-rise leading to necrosis but not to apoptosis in human astrocytes. The cytosolic Ca2+-increase and cellular necrosis depend on the activation of the ATP-sensitive PY2-receptor. Nimodipine had no protective effect on astrocytes in vitro.