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. NeuroReport 12:2619-2622 (C) 2001 Lippincott Williams & Wilkins.