Process extension and intracellular Ca2+ in cultured murine oligodendrocytes.
Previous investigations have shown that phorbol esters stimulate process extension in oligodendrocytes (OL), likely by the activation of protein kinase C (PKC). In this report, we demonstrate that treatment of OL with 4beta-phorbol-12, 13-dibutyrate (PDB; 0.1-1 microM) resulted in an increase in intracellular Ca2+ concentration ([Ca2+]i) from 94+/-2 nM (mean+/-S.E.M.) to 244+/-10 nM. This increase was produced by Ca2+ influx through a La3+-insensitive pathway. Changes in [Ca2+]i were also produced by modifying the extracellular Ca2+ concentration ([Ca2+]o) where [Ca2+]i was increased by elevations in [Ca2+]o. In parallel experiments we found that increased [Ca2+]o alone, without concurrent phorbol ester application, resulted in increased OL process extension as determined by the percent of OL with long processes (greater than 3 times the cell body diameter). These results demonstrate that increasing [Ca2+]o stimulates OL process outgrowth. Furthermore, both elevations in [Ca2+]o and PDB exposure increase [Ca2+]i, suggesting that some of the effects of phorbol esters on OL process extension are likely mediated by changes in [Ca2+]i.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D002273:Carcinogens / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005456:Fluorescent Dyes; D016257:Fura-2; D007211:Indoles / Q000494:pharmacology; D007811:Lanthanum / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D009836:Oligodendroglia / Q000737:chemistry / Q000166:cytology / Q000201:enzymology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism