Hypoxic regulation of Ca2+ signalling in astrocytes and endothelial cells

Peers, C., Kemp, Paul J. ORCID: https://orcid.org/0000-0003-2773-973X, Boyle, J. P., Porter, K. E., Pearson, H. A., Smith, I. F. and Kemp, P. J. 2006. Hypoxic regulation of Ca2+ signalling in astrocytes and endothelial cells. Chadwick, Derek and Goode, Jamie, eds. Signalling Pathways in Acute Oxygen Sensing: Novartis Foundation Symposium 272, Wiley-Blackwell, pp. 119-127. (10.1002/9780470035009.ch10)

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Abstract

Acute hypoxia is well known to modulate plasmalemmal ion channels in specific tissue types, thereby modulating [Ca2+]i. Alternative mechanisms by which acute hypoxia could modulate [Ca2+]i are less well explored, particularly in non-excitable cells. Here, we describe experiments employing microfluorimetric recordings from Fura-2-loaded rat cortical astrocytes and human saphenous vein endothelial cells designed to explore any effects of hypoxia (pO2 20–30 mmHg) on [Ca2+]i. In both cell types, hypoxia evoked small rises of [Ca2+]i in the majority of cells during perfusion with a Ca2+-free solution, indicating hypoxia can release Ca2+ from an intracellular pool. Capacitative Ca2+ entry was observed when Ca2+ was subsequently restored to the extracellular solution. These effects were abolished by pre-treatment of cells with thapsigargin or prior application of inositol 1,4,5-trisphosphate (IP3)-generating agonists. Antioxidants fully prevented this effect of hypoxia in both cell types. Mitochondrial uncoupling significantly enhanced the effects of hypoxia in astrocytes, yet markedly suppressed the effects of hypoxia in endothelial cells. Our findings indicate that hypoxia can modulate [Ca2+]i in non-excitable cells; most importantly, it can evoke Ca2+ release from intracellular stores via a mechanism which involves reactive oxygen species. The involvement of mitochondria in this effect appears to be tissue specific.

Item Type:	Book Section
Date Type:	Publication
Status:	Published
Schools:	Biosciences
Subjects:	Q Science > QP Physiology
Uncontrolled Keywords:	hypoxia and Ca2+ signalling; capacitative Ca2+ entry (CCE); inositol 1,4,5-trisphosphate (IP3)-generating agonists; mitochondrial uncoupling; reactive oxygen species (ROS)
Publisher:	Wiley-Blackwell
ISBN:	9780470014578
ISSN:	1528-2511
Last Modified:	28 Oct 2022 08:33
URI:	https://orca.cardiff.ac.uk/id/eprint/71231

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