Biphasic rise caused by extracellular ATP in intracellular calcium concentration in bovine adrenocortical fasciculata cells.
We examined the effect of extracellular ATP on intracellular calcium concentration ([Ca2+]i) in bovine adrenocortical fasciculata cells. The suspended cells and the monolayer cells on coverslips were loaded with fura2. We found that ATP caused a rapid transient rise [Ca2+]i in dose-dependent manner in the presence of extracellular Ca2+ and that the rise in [Ca2+]i caused by ATP was biphasic. We did not observe the second phase in the absence of extracellular Ca2+. These results suggest that the first rise in [Ca2+]i caused by ATP is due to Ca2+ release from intracellular Ca2+ stores and subsequent rise due to Ca2+ influx across the plasma membrane. Furthermore, we found that the first phase of the monolayer cells consisted of two peaks. So it is possible that Ca2+ release from intracellular Ca2+ stores caused by ATP is induced by two different manners in adrenocortical fasciculata cells. In addition, monolayer cells are more useful than suspended ones in the examination of Ca2+ mobilization in adrenocortical fasciculata cells.
Matsui
T
T
Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan.
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D015383:Zona Fasciculata / Q000378:metabolism*
D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D002122:Calcium Chloride; D002118:Calcium