Extracellular ATP induces spikes in cytosolic free Ca(2+) but not in NADPH oxidase activity in neutrophils
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In order to establish whether non-mitochondrial oxidase activity in human neutrophils is tightly related to cytosolic Ca(2+) concentration, we simultaneously measured Ca(2+) oscillations induced by ATP and oxidant production in single adherent neutrophils using confocal microscopy. ATP induced fast damped Ca(2+) spikes with a period of 15s and slower irregular spikes with a period greater than 50s. Spikes in Ca(2+) occurred in the absence of Ca(2+) influx, but the amplitude was damped by inhibition of Ca(2+) influx. Using the oxidation of hydroethidine as a cytosolic marker of oxidant production, we show that the generation of reactive oxygen species by neutrophils adherent to glass was accelerated by ATP. The step-up in NADPH oxidase activity followed the first elevation of cytosolic Ca(2+) but, despite subsequent spikes in Ca(2+) concentration, no oscillations in oxidase activity could be detected. ATP induced spikes in Ca(2+) in a very reproducible way and we propose that the Ca(2+) signal is an on-switch for oxidase activity, but the activity is apparently not directly correlated with spiking activity in cytosolic Ca(2+).
Originalsprog | Engelsk |
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Tidsskrift | B B A - Molecular Cell Research |
Vol/bind | 1813 |
Udgave nummer | 8 |
Sider (fra-til) | 1446-52 |
Antal sider | 7 |
ISSN | 0167-4889 |
DOI | |
Status | Udgivet - 1 aug. 2011 |
ID: 33684407