Mechanisms of histamine-induced intracellular Ca2+ release and extracellular Ca2+ entry in MG63 human osteosarcoma cells.
The effect of histamine on intracellular free Ca2+ levels ([Ca2+](i)) in MG63 human osteosarcoma cells was explored using fura-2 as a Ca2+ dye. Histamine increased ([Ca2+](i)) in a concentration-dependent fashion with an EC(50) value of 0.5 microM. Extracellular Ca2+ removal inhibited the ([Ca2+](i)) signals. Histamine failed to increase ([Ca2+](i)) in Ca2+-free medium after cells were pretreated with thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). Addition of Ca2+ induced concentration-dependent ([Ca2+](i)) increases after preincubation with histamine in Ca2+-free medium. Histamine-induced intracellular Ca2+ release was abolished by inhibiting phospholipase C with 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). The ([Ca2+](i)) increase induced by histamine in Ca2+ medium was abolished by cimetidine, but was not altered by pyrilamine, nifedipine, verapamil, and La(3+). Together, this study shows that histamine increased in ([Ca2+](i)) in osteosarcoma cells by stimulating H2 histamine receptors. The Ca2+ signal was caused by Ca2+ release from the endoplasmic reticulum in a phospholipase C-dependent manner. The Ca2+ release was accompanied by Ca(2+) influx.
Lee
K C
KC
Department of Internal Medicine, Kaohsiung Veterans General Hospital, 386 Ta Chung 1st Road, Kaohsiung, Taiwan
Tseng
L L
LL
Chen
Y C
YC
Wang
J W
JW
Lu
C H
CH
Cheng
J S
JS
Wang
J L
JL
Lo
Y K
YK
Jan
C R
CR
D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D006632:Histamine / Q000494:pharmacology*; D006633:Histamine Antagonists / Q000494:pharmacology; D006801:Humans; D012516:Osteosarcoma; D011968:Receptors, Histamine / Q000378:metabolism; D014407:Tumor Cells, Cultured
D006633:Histamine Antagonists; D011968:Receptors, Histamine; D006632:Histamine; D002118:Calcium