Research paperPotentiation by ATP of lipopolysaccharide-stimulated nitric oxide production in cultured astrocytes
Section snippets
Materials
LPS (from Salmonella enteritidis), 2′- and 3′-O-(4-benzoylbenzoyl)-ATP (BzATP), and ATP-2′,3′-dialdehyde (o-ATP; periodate-oxidized ATP) were purchased from Sigma Chemical Co. (St Louis, MO, USA). 2-Methylthioadenosine triphosphate (2-MeSATP) was purchased from Tocris (Bristol, UK). Dulbecco’s modified Eagle’s medium (DMEM) was obtained from Gibco BRL (Grand Island, NY, USA). Fetal calf serum (FCS) was obtained from Filtron (Brooklyn, Australia).
Preparation of astrocyte culture
This study was carried out in compliance with the
Enhancement by ATP of LPS-induced NO production from cultured astrocytes
The concentration of NO2 in the medium of cultured astrocytes was measured for more than 30 h (Fig. 1). The addition of 1.5-mM ATP alone showed no effect compared with the background. The addition of 100 ng/ml LPS induced a large amount of NO production after several hours’ lag time. In the presence of 1.5-mM ATP, LPS-induced NO production was remarkably increased. The lag time was not changed but the slope of the increase became about twice. When the cells were treated with 1.0 ng/ml of LPS,
Discussion
One of the most important findings in this study is that ATP enhanced NO production from cultured astrocytes remarkably. We examined the mechanism of this ATP enhancement of NO production. In the time course of NO2 accumulation in the medium, the addition of ATP did not affect the lag time of NO2 accumulation after LPS addition, but increased the slope thereafter. The lag time seems to be the period necessary for induction of iNOS enzyme; therefore, ATP is likely to enhance iNOS activity
References (32)
- et al.
Agmatine suppresses nitric oxide production in microglia
Brain Res
(2000) - et al.
Inhibitory effects of negatively charged liposomes on nitric oxide production from macrophages stimulated by LPS
Biochem Biophys Res Commun
(1996) - et al.
Endothelial nitric oxide synthaseN-terminal myristoylation determines subcellular localization
J Biol Chem
(1993) - et al.
ATPan extracellular signaling molecule between neurons and glia
Trends Neurosci
(2000) - et al.
Angiotensin II-induced calcium signalling in neurons and astrocytes of rat circumventricular organs
Neuroscience
(1998) - et al.
Delayed increase in neuronal nitric oxide synthase immunoreactivity in thalamus and other brain regions after hypoxic-ischemic injury in neonatal rats
Exp Neurol
(2001) - et al.
Induction of endothelial nitric-oxide synthase in rat brain astrocytes by systemic lipopolysaccharide treatment
J Biol Chem
(2000) - et al.
Extracellular accumulation of nitric oxide, hydrogen peroxide, and glutamate in astrocytic cultures following glutathione depletion, complex I inhibition, and/or lipopolysaccharide-induced activation
Biochem Pharmacol
(2000) - et al.
Differential regulation of microglial NO production by protein kinase C inhibition
Neurochem Int
(2001) - et al.
A study of the mechanism of the release of ATP from rat cortical astroglial cells evoked by activation of glutamate receptors
Neuroscience
(1999)