Artikel
SAH-induced endothelial cytosolic calcium oscillations are ER Ca2+--ATPase dependent
SAB-induzierte endotheliale zytosolische Kalziumoszillationen sind von der Funktion der Ca2+--ATPase des endoplasmatischen Retikulums abhängig
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Autoren
Veröffentlicht: | 23. April 2004 |
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Gliederung
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Objective
After subarachnoid hemorrhage (SAH) cerebral endothelial cells are exposed to extravasal lytic hemoglobin as well as to products of reactions of the surrounding tissue and the immunological response. The aim of the present study was to investigate whether these factors are able to influence the endothelial cytosolic Ca2+ concentration after SAH.
Methods
As experimental model HUVEC (human umbilical cord vein endothelial cells) were incubated with cisternal cerebrospinal fluid (CSF) of 8 patients with SAH. Four of these patients had cerebral vasospasm. In control experiments we used native CSF. HUVEC were loaded with the fluorescence Ca2+ indicator FURA-2. The emitted fluorescence light was collected with an inverted microscope adapted to a video imaging system.
Results
Incubation of HUVEC with SAH-CSF provoked cytosolic Ca2+ oscillations in 6 of 8 cases. After perfusion with CSF sampled from patients with cerebral vasospasm (n=4) endothelial Ca2+ oscillations appeared immediately in all cases. The oscillation frequency was 0,27±0,016 min-1 (mean value±SEM; n=44 cells). In presence of thapsigargin ( 50 nM), an inhibitor of ER Ca2+--ATPase, the oscillations ceased in all cases. In control experiments with native CSF, no oscillations were observed in 6 cases, in 2 cases a minor number of cells showed transient Ca2+ peaks with a frequency of 0.04±0,03 min-1 ( n=8 cells).
Conclusions
Cisternal SAH-CFS, especially from patients with cerebral vasospasms, is able to induce endothelial cytosolic Ca2+ oscillations. These oscillations can be blocked by tapsigargin. This indicates that this oscillation is dependent on the function of endoplasmic reticulum Ca2+--ATPase.