Arachidonic acid influences intracellular calcium handling in human osteoblasts.
The effect of arachidonic acid (AA) on intracellular Ca(2+) concentration ([Ca(2+)]i) in human osteoblasts MG63 was studied. AA caused a concentration-dependent increase in [Ca(2+)]i, mainly due to inward Ca(2+) transport from extracellular environment. Moreover, AA in Ca(2+) -free medium produced a small, transient increase of [Ca(2+)]i, indicating that AA may also trigger Ca(2+) release from intracellular stores. Because the [Ca(2+)]i response to AA was inhibited by the cyclooxygenase (COX) inhibitor indomethacin, we tested the effect of prostaglandins (PGs), products of COX pathway. PGs E1 and E2 caused an increase in [Ca(2+)]i, which, however, was far lower than that obtained with AA. The [Ca(2+)]i response to AA was not inhibited by nifedipine, suggesting that AA did not activate a voltage-dependent Ca(2+) channel. Our results indicate that AA could modulate [Ca(2+)]i in MG63 human osteoblasts, where it may influence Ca(2+) transport across both plasma and endoplasmic membranes. Furthermore, they suggest that osteoblast activity may be modulated by AA.
Soldati
Laura
L
Department of Sciences and Biomedical Technologies, University of Milan, Via Fratelli Cervi 93, 20090, Segrate (Mi), Italy. laura.soldati@unimi.it
Terranegra
Annalisa
A
Baggio
Bruno
B
Biasion
Rita
R
Arcidiacono
Teresa
T
Priante
Giovanna
G
Cusi
Daniele
D
Vezzoli
Giuseppe
G
D000527:Alprostadil / Q000494:pharmacology; D016718:Arachidonic Acid / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002460:Cell Line; D015232:Dinoprostone / Q000494:pharmacology; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism*
D016718:Arachidonic Acid; D000527:Alprostadil; D015232:Dinoprostone; D002118:Calcium