Module 7: Figure astrocyte Ca2+ signalling
Different modes of Ca2+ signalling in astrocytes.
Astrocytes display different modes of Ca2+ signalling depending on the intensity of synaptic activity in the associated nerve endings. At low levels of synaptic transmission, the astrocytes receive little stimulation, and the resulting Ca2+ signal is confined to microdomains within the branches close to the synapse (top left). At higher levels of stimulation, these microdomains tend to spawn an intracellular Ca2+ wave that spreads the signal throughout the astrocyte and down to the endfoot (top right). In general, these regenerative waves tend to be confined to single astrocytes, but during more intense stimulation and under more pathological conditions, intercellular waves can spread from astrocyte to astrocyte, as shown at the bottom.