| Popis: |
Publisher Summary This chapter presents evidence consistent with the suggestion that the modulation of certain neuronal functions by extracellular adenosine triphosphate (ATP) involves the activity of extracellular protein kinases, which phosphorylate proteins localized at the outer surface of the plasma membrane of neural cells. Several lines of investigation have provided evidence that extracellular ATP exerts potent effects on the activity of excitable cells, neurons and muscle. In addition to its role as a neurotransmitter, extracellular ATP can also serve as a modulator, regulating the activity of other neurohormones. One well-documented modulatory effect of extracellular ATP is the inhibition of evoked quantal acetylcholine secretion. Recent studies have demonstrated that when ATP is applied extracellularly to preganglionic nerves, it inhibits acetylcholine release. The cells of the neuroblastoma X glioma hybrid line, NG108-15, grown and differentiated in a chemically defined medium, are used to demonstrate the presence of an ecto-protein kinase and specific substrates for its activity at the surface of neural cells. |
