Local energy on demand: are 'spontaneous' astrocytic Ca(2+)-microdomains the regulatory unit for astrocyte-neuron metabolic cooperation?

Local energy on demand: are 'spontaneous' astrocytic Ca(2+)-microdomains the regulatory unit for astrocyte-neuron metabolic cooperation? Brain Res Bull. 2017 Apr 24;: Authors: Oheim M, Schmidt E, Hirrlinger J Abstract Astrocytes are a neural cell type critically involved in maintaining brain energy homeostasis as well as signaling. Like neurons, astrocytes are a heterogeneous cell population. Cortical astrocytes show a complex morphology with a highly branched aborization and numerous fine processes ensheathing the synapses of neighboring neurons, and typically extend one process connecting to blood vessels. Recent studies employing genetically encoded fluorescent calcium (Ca(2+)) indicators have described 'spontaneous' localized Ca(2+)-transients in the astrocyte periphery that occur asynchronously, independently of signals in other parts of the cells, and that do not involve somatic Ca(2+) transients; however, neither it is known whether these Ca(2+)-microdomains occur at or near neuronal synapses nor have their molecular basis nor downstream effector(s) been identified. In addition to Ca(2+) microdomains, sodium (Na(+)) transients occur in astrocyte subdomains, too, most likely as a consequence of Na(+) co-transport with the neurotransmitter glutamate, which also regulates mitochondrial movements locally - as do cytoplasmic Ca(2+) levels. In this review, we cover various aspects of these local signaling events and discuss how stru...
Source: Brain Research Bulletin - Category: Neurology Authors: Tags: Brain Res Bull Source Type: research