[14C]GLUTAMATE UPTAKE AND COMPARTMENTATION IN GLIA OF RAT DORSAL SENSORY GANGLION |
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Authors: | P. J. Roberts P. Keen |
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Affiliation: | Department of Pharmacology, The Middlesex Hospital Medical School, London W1P 7PN, and The Medical School, University Walk, Bristol BS8 1TD, England |
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Abstract: | Abstract— The characteristics of the uptake of l -[U-14C] glutamate into rat dorsal sensory ganglia were investigated. The uptake was mediated by two distinct kinetic systems, with apparent Km values of the order of 10−3 M (low affinity) and 10−5 m (high affinity). The high affinity uptake system was strongly dependent upon temperature and sodium ion concn, and was depressed by a number of metabolic inhibitors. Following uptake, [14C] glutamate was extensively metabolized, primarily to glutamine, although this was not so with cultured ganglia, where in addition to an increased uptake of [14C] glutamate, the specific radioactivity of glutamate was increased and that of glutamine decreased. The labelled substrates [U-14C]pyruvate and [U-14C] acetate were used to investigate this phenomenon and the results are discussed in relation to current knowledge of metabolic compartmentation in nervous tissue. |
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