Platelet-activating factor evokes Ca2+ transients after the blockade of ryanodine receptor by dantrolene in RAW 264.7 macrophages

Citation
B. Lendvai et al., Platelet-activating factor evokes Ca2+ transients after the blockade of ryanodine receptor by dantrolene in RAW 264.7 macrophages, NEUROCHEM R, 26(8-9), 2001, pp. 1007-1013
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences & Behavoir
Journal title
NEUROCHEMICAL RESEARCH
ISSN journal
0364-3190 → ACNP
Volume
26
Issue
8-9
Year of publication
2001
Pages
1007 - 1013
Database
ISI
SICI code
0364-3190(200109)26:8-9<1007:PFECTA>2.0.ZU;2-7
Abstract
In the present study we studied platelet-activating factor (PAF)-, and ATP- induced increases in intracellular Ca2+ concentration ([Ca2+](i)) using RAW 264.7 macrophages filled with fura-2/AM and imaged with fluorescence video microscopy. We found that the prevalence of detectable [Ca-2+](i) response s to PAF application was significantly higher in the presence of dantrolene . Dantrolene itself significantly decreased basal [Ca2+](i) of macrophages compared to control cases after a 20-min incubation period. In the dantrole ne-treated cells even the peak [Ca2+](i) in response to PAF (as an average of all cells) was below the baseline of control suggesting that decreased [ Ca2+](i) plays a permissive role in the Ca2+ rise induced by PAF in macroph ages. In contrast to the effect of PAF, neither the amplitude of response t o ATP nor the frequency of responding cells changed significantly during da ntrolene treatment in our experiments. These cells were able to respond to a standard immune stimulus as well: lipopolysaccharide (LPS) was able to in crease [Ca2+](i). Our data indicate that the effectiveness of PAF to increa se [Ca2+](i) in RAW 264.7 macrophages depends on the resting [Ca2+](i). It has also been shown in this study that PAF and ATP differently regulate Ca2 + homeostasis in macrophages during inflammatory response and therefore the y possibly differently modulate cytokine production by macrophages.