Lysophosphatidic acid as a stimulator of Na(+)-dependent Ca2+ efflux from adrenal chromaffin cells.
The effect of lysophosphatidic acid (LPA) on Ca2+ efflux from cultured bovine adrenal chromaffin cells was examined. LPA stimulated the efflux of 45Ca2+ from the cells in a concentration dependent manner (10(-7)-10(-5)M). Other lysophospholipids (lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylinositol and lysophosphatidylserine), phosphatidic acid, monoolein and oleic acid had not significant effect on 45Ca2+ efflux from the cells. The LPA-stimulated 45Ca2+ efflux was dependent on the extracellular Na+ concentration and was inhibited by amiloride, inhibitor of Na+/Ca2+ exchange. LPA increased 22Na+ uptake into the cells and this effect was also sensitive to amiloride. These results indicate that LPA stimulates extracellular Na(+)-dependent 45Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably through its stimulatory effect on membrane Na+/Ca2+ exchange.
Houchi
H
H
Department of Pharmacology, School of Medicine, University of Tokushima, Japan.
Okuno
M
M
Tokumura
A
A
Yoshizumi
M
M
Fukuzawa
K
K
Oka
M
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008246:Lysophospholipids / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology*; D013997:Time Factors
D008246:Lysophospholipids; D012964:Sodium; D002118:Calcium