Osmotically induced cytosolic free Ca2+ changes in human neutrophils
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- 作者：Morris ; M. Rachel ; Doull ; Iolo J.M. ; Hallett ; Maurice B.
- 关键词：Neutrophil ; Cytosolic free Ca2+ concentration ; Osmolarity ; Cystic fibrosis ; Signalling ; Imaging ; Cell shape ; (Lung damage) ; (Inflammation)
- 刊名：Biochimica et Biophysica Acta (BBA)/Molecular Cell Research
- 出版年：2001
- 出版时间：February 5, 2001
- 年：2001
- 卷：1538
- 期：1
- 页码：20-27
- 全文大小：370 K
文摘
Cytosolic free Ca2+ concentration in neutrophils was measured by ratiometric fluorometry of intracellular fura2. Increasing the extracellular osmolarity, by either NaCl (300–600 mM) or sucrose (600–1200 mM), caused a rise in cytosolic free Ca2+ (Δmax
600 nM). This was not due to cell lysis as the cytosolic free Ca2+ concentration was reversed by restoration of isotonicity and a second rise in cytosolic free Ca2+ could be provoked by repeating the change in extracellular osmolarity. Furthermore, the rise in cytosolic free Ca2+ concentration occurred in the absence of extracellular Ca2+, demonstrating that release of intracellular fura2 into the external medium did not occur. The osmotically-induced rise in cytosolic free Ca2+ was not inhibited by either the phospholipase C-inhibitor U73122, or the microfilament inhibitor cytochalasin B, suggesting that neither signalling via inositol tris-phosphate or the cytoskeletal system were involved. However, the rise in cytosolic free Ca2+ may have resulted from a reduction in neutrophil water volume in hyperosmotic conditions. As these rises in cytosolic Ca2+ (Δmax600 nM) were large enough to provoke changes in neutrophil activity, we propose that conditions which removes cell water may similarly elevate cytosolic free Ca2+ to physiologically important levels.
600 nM). This was not due to cell lysis as the cytosolic free Ca2+ concentration was reversed by restoration of isotonicity and a second rise in cytosolic free Ca2+ could be provoked by repeating the change in extracellular osmolarity. Furthermore, the rise in cytosolic free Ca2+ concentration occurred in the absence of extracellular Ca2+, demonstrating that release of intracellular fura2 into the external medium did not occur. The osmotically-induced rise in cytosolic free Ca2+ was not inhibited by either the phospholipase C-inhibitor U73122, or the microfilament inhibitor cytochalasin B, suggesting that neither signalling via inositol tris-phosphate or the cytoskeletal system were involved. However, the rise in cytosolic free Ca2+ may have resulted from a reduction in neutrophil water volume in hyperosmotic conditions. As these rises in cytosolic Ca2+ (Δmax600 nM) were large enough to provoke changes in neutrophil activity, we propose that conditions which removes cell water may similarly elevate cytosolic free Ca2+ to physiologically important levels.