Sphingolipid derivatives modulate intracellular Ca2+ in rat synaptosomes.
Sphingosylphosphorylcholine (SPC) induces a rapid increase of intracellular Ca2+ concentration in isolated synaptosomes. This effect is dose-dependent and is also dependent on extracellular Ca2+. Sphingosine (SPH) has a smaller effect and treatment with psychosine (PSY) is ineffective, which suggests that phosphorylation of the 1-carbon of SPH is required for the SPC to act as a Ca2+ release agonist in synaptosomes. Experiments performed in the presence of heparin or ryanodine indicate that SPC-elicited Ca2+ release is not mediated by IP3 or ryanodine receptors. Finally, our results show that the effect of SPC on Ca2+ concentration is nimodipine-sensitive, suggesting that SPC possibly activates a specific sphingolipid-gated Ca2+ channel in synaptosomes.
Miguel
B G
BG
Department of Biochemistry and Molecular Biology I, Faculty of Chemistry, Complutense University, E-28040 Madrid, Spain.
Calcerrada
M C
MC
Catalán
R E
RE
Martínez
A M
AM
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D009553:Nimodipine / Q000494:pharmacology; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000494:pharmacology*; D011609:Psychosine / Q000494:pharmacology; D051381:Rats; D012433:Ryanodine / Q000494:pharmacology; D013107:Sphingolipids / Q000494:pharmacology*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D000925:Anticoagulants; D002121:Calcium Channel Blockers; D013107:Sphingolipids; C005356:sphingosine phosphorylcholine; D010767:Phosphorylcholine; D012433:Ryanodine; D011609:Psychosine; D009553:Nimodipine; D006493:Heparin; D013110:Sphingosine; D002118:Calcium