TY - JOUR
T1 - Extracellular ATP induces spikes in cytosolic free Ca(2+) but not in NADPH oxidase activity in neutrophils
AU - Brasen, Jens Christian
AU - Olsen, Lars Folke
AU - Hallett, Maurice B
N1 - Copyright © 2011 Elsevier B.V. All rights reserved.
PY - 2011/8/1
Y1 - 2011/8/1
N2 - 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+).
AB - 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+).
U2 - 10.1016/j.bbamcr.2011.05.002
DO - 10.1016/j.bbamcr.2011.05.002
M3 - Journal article
C2 - 21596069
SN - 0167-4889
VL - 1813
SP - 1446
EP - 1452
JO - B B A - Molecular Cell Research
JF - B B A - Molecular Cell Research
IS - 8
ER -