Mechanisms of glutamate release from astrocytes.
Astrocytes can release the excitatory transmitter glutamate which is capable of modulating activity in nearby neurons. This astrocytic glutamate release can occur through six known mechanisms: (i) reversal of uptake by glutamate transporters (ii) anion channel opening induced by cell swelling, (iii) Ca2+-dependent exocytosis, (iv) glutamate exchange via the cystine-glutamate antiporter, (v) release through ionotropic purinergic receptors and (vi) functional unpaired connexons, "hemichannels", on the cell surface. Although these various pathways have been defined, it is not clear how often and to what extent astrocytes employ different mechanisms. It will be necessary to determine whether the same glutamate release mechanisms that operate under physiological conditions operate during pathological conditions or whether there are specific release mechanisms that operate under particular conditions.
Malarkey
Erik B
EB
Department of Cell Biology & Neuroscience, Center for Glial-Neuronal Interactions, University of California, Riverside, CA 92521, United States.
Parpura
Vladimir
V
D027322:Amino Acid Transport System X-AG / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D005089:Exocytosis; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000378:metabolism; D058486:Receptors, Purinergic P2X7
D027322:Amino Acid Transport System X-AG; D007473:Ion Channels; C546468:P2RX7 protein, human; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D018698:Glutamic Acid; D002118:Calcium