Alterations in the metabolism of choline-containing phospholipids by lithium and carbachol in SH-SY5Y neuroblastoma cells.
To investigate choline phospholipid metabolism in the human neuroblastoma cell line SH-SY5Y, cultures labeled with [14C-methyl]choline were incubated for up to 30 min in Krebs-Ringer-glucose-N-2-hydroxyethyl-piperazine-N1-2-ethane sulfonic acid (HEPES) buffer with or without 10 mmol/L LiCl. When desired, 1 mmol/L of the muscarinic agonist carbamoylcholine was present during the last minute of incubation. When cells were exposed for 10 min to lithium, radioactivity in phosphatidylcholine, lysophosphatidylcholine, and sphingomyelin was 40%-140% higher than in controls incubated in buffer only. This contrasted with the results from carbamoylcholine-containing incubations, which gave radioactivities lower than or equal to controls. Carbamoylcholine added to the LiCl-containing incubations yielded results only minimally different from LiCl alone. Phosphorylcholine radioactivity was also elevated by about 50% after 10 min incubation with LiCl with or without added carbamoylcholine, but was not increased in incubations with the agonist by itself. Similar changes were observed for intracellular choline but after only 5 min. These data suggest that carbamoylcholine does not stimulate phosphatidylcholine degradation, whereas LiCl can significantly affect its metabolism and may affect signal transduction via second messengers in human neuroblastoma cells.
Liepkalns
V A
VA
Ralph Lowell Laboratories, McLean Hospital, Belmont, MA.
Leli
U
U
Hauser
G
G
D002217:Carbachol / Q000494:pharmacology*; D002794:Choline / Q000032:analysis; D006801:Humans; D008094:Lithium / Q000494:pharmacology*; D009447:Neuroblastoma / Q000378:metabolism* / Q000648:ultrastructure; D010740:Phospholipases / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000378:metabolism* / Q000648:ultrastructure
D010743:Phospholipids; D002217:Carbachol; D008094:Lithium; D010740:Phospholipases; D002794:Choline