[3H]Choline Uptake and Metabolism in Nonsynaptic Regions of a Crustacean Sensory Nerve |
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Authors: | Anthony Auerbach David L Barker |
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Institution: | Department of Biology, University of Oregon, Eugene, Oregon, U.S.A. |
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Abstract: | Abstract: The posterior stomach nerve (PSN) is a crustacean sensory nerve containing about 60 cholinergic neurons, which are devoid of synaptic interactions. Kinetic analysis shows that the PSN takes up 3H]choline by both low-affinity ( K m= 163 μM) and high-affinity (Na+-dependent) ( K m= 1 μM) processes. The capacity of the high-affinity system is only about 1% that of the low-affinity system. The high-affinity system is not tightly coupled to acetylcholine (ACh) synthesis, and it appears that both ACh and phosphorylcholine are formed from an intracellular pool of choline, which is fed by both uptake systems. There are differences in the rates of 3H]choline uptake and 3H metabolite accumulation between regions of the PSN that contain neuronal cell bodies and those that do not. These differences may arise from differences in the relative proportion of neuronal to nonneuronal tissue in each nerve region. |
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Keywords: | High-affinity uptake Choline Acetylcholine synthesis Sensory nerves (crustacean) |
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