Choline Uptake and Metabolism in Affinity-Purified Cholinergic Nerve Terminals from Rat Brain |
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Authors: | Peter J Richardson |
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Institution: | University of Cambridge and Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge, England |
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Abstract: | Cholinergic nerve terminals were affinity purified from rat caudate nucleus. These terminals possessed both high- (KT = 2.7 microM) and low- (KT = 58 microM) affinity uptake mechanisms for exogenous 3H]choline. The proportion of 3H]choline acetylated was reduced from 75 to 30% under conditions of anoxia and hypoglycaemia, whereas the phosphorylation of choline increased from 4 to 52%. Choline phosphorylation was also increased when the terminals were preloaded with choline. The affinity-purified terminals were shown to release acetylcholine in a Ca2+-dependent manner on depolarization. The relationship between choline acetylation and phosphorylation in the cholinergic nerve terminal is discussed. |
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Keywords: | Affinity purification Choline uptake Acetylcholine |
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