Regulation of cytosolic free Ca2+ in cultured rat alveolar macrophages (NR8383).
Ca2+ mobilization in the rat alveolar macrophage cell line NR8383 was examined with the Ca2+-sensitive fluorescent probe Fura-2. ATP and norepinephrine elicited a 108 and 46% increase, respectively, in cytosolic free Ca2+ concentration ([Ca2+]i). Acetylcholine, nicotine, isoproterenol, substance P, and vasoactive intestinal polypeptide did not alter [Ca2+]i. Inositol 1,4,5-trisphosphate (IP3) formation was also activated by ATP. The carbohydrate-rich cell wall preparation, zymosan, induced a gradual [Ca2+]i, increase only in the presence of external Ca2+, but did not activate IP3 formation. This increase was abolished by laminarin and by removal of extracellular Ca2+, suggesting that the [Ca2+]i increase was activated by beta-glucan receptors and mediated by Ca2+ influx. This influx was significantly reduced by SKF96365, but not by nifedipine, (omega-conotoxin GVIA, (omega-agatoxin IVA, or flunarizine. These results suggest that release of intracellular Ca2+ in NR8383 cells is regulated by P2-purinoceptors and that zymosan causes Ca2+ influx via a receptor-operated pathway.
Zhang
G H
GH
Department of Pediatrics, University of Texas Health Science Center at San Antonio, 78284, USA.
Helmke
R J
RJ
Mörk
A C
AC
Martinez
J R
JR
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis*; D016676:Macrophages, Alveolar / Q000378:metabolism*; D008564:Membrane Potentials; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology; D015054:Zymosan / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007093:Imidazoles; D018048:Receptors, Purinergic P2; D019284:Thapsigargin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D015054:Zymosan; D000252:Calcium-Transporting ATPases; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D002118:Calcium