The trophic effects of purines and purinergic signaling in pathologicreactions of astrocytes
M.P. Rathbone
Bok Engelsk 1998
| Utgitt | 1998
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|---|---|
| Omfang | Side S36- S45
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| Opplysninger | This article reviews the effects of extracellular purine bases,nucleosides, and nucleotides as intracellular signaling moleculeswith trophic effects on cells after insults to the brain and spinalcord. Astrocytes are the principal source of extracellular purines inbrain after injury, ischemia, or trauma. In vitro and in vivoextracellular purines have both immediate and long-term trophiceffects, including stimulation of astrocyte and neuronaldifferentiation, mitosis, morphogenesis, apoptosis, and stimulationof growth and trophic factor synthesis. The effects of the nucleosideadenosine and the nucleotide adenosine triphosphate (ATP) aremediated principally via specific receptors on the cell surfacecoupled to a series of signaling cascades. Unlike adenosine and ATP,guanosine and guanosine triphosphate (GTP) do not act at classicalpurine receptors. However, they exert similar effects on astrocytes,apparently by causing the astrocytes to release large amounts ofadenosine and ATP over prolonged periods. The release of adenosineand ATP may be related to the effects of guanosine on the purinenucleoside transporters in the cell membrane, whereas the release ofATP may be due to the effects of GTP on the ATP-binding cassette(ABC) proteins. Physiologically, the effects of guanosine areimportant because this nucleoside, unlike adenosine, remains elevatedfor prolonged periods after brain injury.
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| Emner |
