Synaptosomal Phospholipase D Potential Role in Providing Choline for Acetylcholine Synthesis |
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Authors: | Hiroshi Hattori Julian N Kanfer |
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Institution: | Department of Biochemistry, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada |
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Abstract: | The phospholipase D of the rat brain synaptic membrane possesses the highest activity of this enzyme of any mammalian tissue examined. The synaptic phospholipase D activity is latent and barely detectable in the absence of 4 mM sodium oleate. Several other fatty acids were either less effective or ineffective as stimulators of activity compared to this monounsaturated fatty acid. The activity was decreased by hemicholinium-3, an inhibitor of choline uptake and slightly activated by neostigmine, an acetylcholinesterase inhibitor. Incubation of synaptosomes in the presence of sodium oleate and acetyl-coenzyme A resulted in the formation of a product chromatographing with acetylcholine. Acetylcholine formation was nearly undetectable in the absence of sodium oleate or acetyl-coenzyme A. These results implicate synaptosomal phospholipase D in releasing choline from phosphatidylcholine for acetylcholine formation. |
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Keywords: | Phospholipase D Choline Acetylcholine Synaptic membranes |
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