科研之友
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摘要
Vesicular glutamate release from astrocytes depends on mobilization of free Ca2+ from the endoplasmic reticulum ( ER), and extracellular space to elevate cytosolic Ca2+ (Ca-cyt(2+)). Although mitochondria in neurons, and other secretory cells, have been shown to sequester free Ca2+ and have been implicated in the modulation of Ca2+-dependent transmitter release, the role of mitochondria in Ca2+-dependent glutamate release from astrocytes is not known. A pharmacological approach was taken to manipulate Ca2+ accumulation in mitochondria and thereby affect Ca-cyt(2+) of solitary astrocytes in response to mechanical stimuli. Ca-cyt(2+) responses and levels of glutamate release were measured optically in parallel experiments using a fluorescent Ca2+ indicator and an enzyme-linked assay, respectively. It was observed that inhibiting mitochondrial Ca2+ accumulation is correlated to increased Ca-cyt(2+) and glutamate release, whereas enhancing mitochondrial Ca2+ accumulation is correlated to decreased Ca-cyt(2+) and glutamate release. These observations suggest that, in addition to the activity of ER and plasma membrane ion channels, mitochondria modulate Ca-cyt(2+) dynamics in astrocytes and play a role in Ca2+-dependent glutamate release from astrocytes.
- 出版日期2008-9-24
