Figure 3. Astrocytes have several types of ionotropic and metabotropic membrane receptor for ATP and its breakdown products, ADP, AMP and adenosine, which increase intracellular calcium concentrations.
Calcium transients and waves induced by extracellular ATP are important in intercellular communication between astrocytes and between neurons and astrocytes. a | Rat astrocytes in culture. b | Application of 100 μM ATP to cultured rat astrocytes resulted in rapid and large increases in intracellular calcium concentrations. c | Shows recovery after a 15 min wash. Intracellular calcium concentration was monitored using confocal microscopy to measure the fluorescence intensity of the calcium-sensitive indicator, fluo-4. High concentrations of intracellular calcium are indicated in yellow and orange.