Ca2+ signaling regulated by an ATP-dependent autocrine mechanism in astrocytes.
Although the mechanisms of Ca2+ wave propagation in astrocytes induced by mechanical stimulation have been well studied, it is still not known how the [Ca2+]i increases in the stimulated cells. Here, we have analyzed the mechanisms of [Ca2+]i increase in single, isolated astrocytes. Our results showed that there was an autocrine mechanism of Ca2+ regulation mediated by ATP in mechanically stimulated astrocytes. This autocrine mechanism induced the activation of phospholipase C via a G-protein, resulting in Ca2+ release from intracellular Ca2+ stores. A second pathway mediating a [Ca2+]i increase was via a Ca2+ influx from the extracellular space, which, interestingly, suppressed an intracellular Ca2+ oscillation. These two different Ca2+ cascades are involved in signal transduction and may function separately during intercellular communication.
Shiga
H
H
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Tojima
T
T
Ito
E
E
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019898:Autocrine Communication / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004963:Estrenes / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism; D007424:Intracellular Fluid / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010812:Physical Stimulation; D058919:Purinergic P2 Receptor Antagonists; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013498:Suramin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
D004963:Estrenes; D010726:Phosphodiesterase Inhibitors; D058919:Purinergic P2 Receptor Antagonists; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D013498:Suramin; D000255:Adenosine Triphosphate; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D002118:Calcium