Mitochondrial dynamics in astrocytes.

Astrocytes exhibit cellular excitability through variations in their intracellular calcium (Ca2+) levels in response to synaptic activity. Astrocyte Ca2+ elevations can trigger the release of neuroactive substances that can modulate synaptic transmission and plasticity, hence promoting bidirectional communication with neurons. Intracellular Ca2+ dynamics can be regulated by several proteins located in the plasma membrane, within the cytosol and by intracellular organelles such as mitochondria. Spatial dynamics and strategic positioning of mitochondria are important for matching local energy provision and Ca2+ buffering requirements to the demands of neuronal signalling. Although relatively unresolved in astrocytes, further understanding the role of mitochondria in astrocytes may reveal more about the complex bidirectional relationship between astrocytes and neurons in health and disease. In the present review, we discuss some recent insights regarding mitochondrial function, transport and turnover in astrocytes and highlight some important questions that remain to be answered.