Modulation of the Rat Alveolar Macrophage Respiratory Burst by Hydroperoxides Is Calcium Dependent

Modulation of the Rat Alveolar Macrophage Respiratory Burst by Hydroperoxides Is Calcium Dependent

Sublethal concentrations of hydroperoxides (H2O2or tert-butylhydroperoxide) produce a dual effect upon the respiratory burst of rat alveolar macrophages in which low concentrations (<50 μM) enhance and higher concentrations (>50 μM) produce inhibition (J. K. Murphy,et al., Free Radical. Biol....

Full description

Saved in:
Bibliographic Details
Published in:Archives of biochemistry and biophysics Vol. 326; no. 1; pp. 166 - 171
Main Authors: Hoyal, Carolyn R., Gozal, Evelyne, Zhou, Huanfang, Foldenauer, Kim, Forman, Henry Jay
Format: Journal Article
Language:English
Published: United States Elsevier Inc 01-02-1996
Subjects:
alveolar macrophage
Animals
calcium
Calcium - metabolism
Enzyme Inhibitors - pharmacology
Hydrogen Peroxide - metabolism
Hydrogen Peroxide - pharmacology
inositol-1,4,5-trisphosphate
Macrophages, Alveolar - metabolism
Male
Oxidants - metabolism
Oxidants - pharmacology
Rats
Rats, Sprague-Dawley
respiratory burst
Respiratory Burst - drug effects
Terpenes - pharmacology
tert-butylhydroperoxide
Thapsigargin
alveolar macrophage
tert-butylhydroperoxide
calcium
inositol-1,4,5-trisphosphate
respiratory burst
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Sublethal concentrations of hydroperoxides (H2O2or tert-butylhydroperoxide) produce a dual effect upon the respiratory burst of rat alveolar macrophages in which low concentrations (<50 μM) enhance and higher concentrations (>50 μM) produce inhibition (J. K. Murphy,et al., Free Radical. Biol. Med.18, 37–45, 1995). These effects correlate with transient versus sustained elevation of [Ca2+]icaused by exposure to hydroperoxides prior to stimulation of the respiratory burst. In the present study changes in [Ca2+]icaused by exposure to sublethal levels of hydroperoxide were buffered by incubating macrophages with the acetoxymethyl ester of BAPTA, an intracellular Ca2+chelator. The enhancement of the phorbol ester-stimulated respiratory burst by tBOOH was abolished by BAPTA, while the inhibition was attenuated. Thus, the modulation by tBOOH appears to be largely dependent upon the changes in [Ca2+]i. Receptor mediated stimulation of the respiratory burst (ADP stimulation) involves release of Ca2+from the inositol-1,4,5-trisphosphate (IP3)-sensitive pool in the endoplasmic reticulum. Comparisons were made of the effects of thapsigargin (TG), an endoplasmic reticulum Ca-ATPase inhibitor, with tBOOH on release of intracellular Ca2+and the respiratory burst. Treatment with TG did not affect changes in [Ca2+]icaused by tBOOH or vice versa. Although TG decreased the ADP-stimulated respiratory burst, it had no effect upon tBOOH modulation. Thus, the effect of tBOOH upon the respiratory burst is dependent upon the release of Ca2+and the release of Ca2+occurs from a non-IP3-dependent pool. This aberrant mimicry of normal signal transduction underlies oxidative modulation of the respiratory burst.
ISSN:0003-9861
1096-0384
DOI:10.1006/abbi.1996.0061