Effects of sphingosine derivatives on MC3T3-E1 pre-osteoblasts: psychosine elicits release of calcium from intracellualr stores.
Sphingosine, sphingosine-1-phosphate (SPP) and sphingosylphosphorylcholine (SPC) each elicited transient elevations in intracellular free Ca2+ ([Ca2+]i) as a result of Ca2+ release from an intracellular store in MC3T3-E1 pre-osteoblasts. No elevation in [Ca2+]i was detected in response to the application of N-acetyl sphingosine. Psychosine (1-galactosyl sphingosine) also caused Ca2+ release from intracellular stores, which suggests that phosphorylation of the 1-carbon of sphingosine is not required for its action as a Ca2+ release agonist in MC3T3-E1 cells. Sequential additions of combinations of sphingosine, SPP, SPC and psychosine revealed Ca2+ transients only after the application of the first sphingolipid, despite the fact that the intracellular Ca2+ stores refilled. This indicates that each agent desensitized the MC3T3-E1 cells to the action of the others and suggests that all of the sphingolipids tested employ the same receptor or a common intracellular messenger.
Liu
R
R
Department of Integrative Biology, University of Texas Medical School, Houston 77225, USA.
Farach-Carson
M C
MC
Karin
N J
NJ
D016475:3T3 Cells; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D007700:Kinetics; D008246:Lysophospholipids; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000494:pharmacology; D011609:Psychosine / Q000494:pharmacology*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D005456:Fluorescent Dyes; D008246:Lysophospholipids; C064769:N-acetylsphingosine; C005356:sphingosine phosphorylcholine; C049925:fura-2-am; D010767:Phosphorylcholine; D011609:Psychosine; C060506:sphingosine 1-phosphate; D013110:Sphingosine; D002118:Calcium; D016257:Fura-2