Teaching resources. Glial intercellular waves.
Glial cells have long been assigned a supporting role in the nervous system, in which they help maintain and modulate neuronal metabolism. However, recent attention has focused on the ability of astrocytes to propagate long-range calcium signals and actively communicate with each other, as well as with neurons and vascular cells. Synaptic activity in neurons triggers an increase in the intracellular calcium concentration ([Ca2+]i) of neighboring astrocytes, stimulating the release of ATP and glutamate. The released ATP stimulates an increase in [Ca2+]i in neighboring astrocytes so that a "calcium wave" is propagated from cell to cell. Released glutamate is cotransported with Na+ into neighboring cells; thus, glutamate uptake leads to an increase in astrocyte intracellular sodium concentration ([Na+]i) that is also propagated from cell to cell. This increase in [Na+]i stimulates an increase in glucose uptake and metabolism that leads to the formation of lactate, which is delivered to nearby--and perhaps distant--neurons as an energy substrate. Thus, long-range intercellular calcium signaling in astrocytes may enable them to spatially coordinate their function in supporting neuronal metabolism.
Charles
Andrew
A
Department of Neurology, David Geffen School of Medicine, UCLA, 710 Westwood Plaza, Los Angeles, CA 90095, USA. acharles@ucla.edu
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D001695:Biology / Q000193:education*; D020013:Calcium Signaling / Q000502:physiology*; D002450:Cell Communication; D018698:Glutamic Acid / Q000378:metabolism; D009040:Motion Pictures; D012964:Sodium / Q000502:physiology*; D009435:Synaptic Transmission
D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D012964:Sodium