Glutamate uptake membranes

Transport proteins (channels) for chloride and zinc Vacuolar proton pump Components of synaptic vesicles to mediate the chloride flux for glutamate uptake and zinc uptake in most synaptic vesicles. Zinc transporter is homologous to endosomal and plasma membrane zinc transporters chloride transporters remain to be identified. Protein complex of more than 12 subunits. Constitutes the largest component of synaptic vesicles and establishes... 

Brew, H. and Attwell, D. (1987) Electrogenic glutamate uptake is a major current carrier in the membrane of axolotl retinal glial cells. Nature 327,707-709. 

The uptake of aminoacid neurotransmitter has been characterized by bioenergetic studies (Hell et ai, 1992 Hartinger and John, 1993). In contrast to catecholamine and GABA uptake, glutamate uptake does not depend on a pH gradient over the vesicle membrane. 

Hertz L., Schousboe A., Boechler N, Mukerji S., and Fedoroff S (1978) Kinetic characteristics of the glutamate uptake into normal astrocytes in culture Neurochem Res 3, 1-14 Hertz L., Yu A, Svenneby G, Kvamme E., Fosmark H., and Schousboe A. (1980) Absence of preferential glutamine uptake into neurons. An indication of a net transfer of TCA constituents from nerve endings to astrocytes Neurosct Lett 16, 103-109 Hoffman E K., Simonsen L O, and Lambert I H (1984) Volume-induced increase of K" and Cr permeabilities in Ehrlich ascites tumor cells Role of internal calcium / Membrane Biol 78, 211-222 Holloway P. W (1973) A simple procedure for removal of triton X-100 from protein samples Anal Biochem 53, 30 308 Hosli E. and Hosli L. (1976) Autoradiographic studies on the uptake of [ H] noradrenaline and [ H] GABA in cultured rat cerebellum Exp Brain Res 26, 319-324... 

Low concentrations of solubilised jS-albumin inhibit ACh release in slices from rat hippocampus and cortex areas which show degeneration in AzD, but not in slices from the striatum which is unaffected. While not totally specific to ACh, since some inhibition of NA and DA and potentiation of glutamate release have been reported, this effect is achieved at concentrations of A/i below those generally neurotoxic. Since jS-amyloid can inhibit choline uptake it is also possible (see Auld, Kar and Quiron 1998) that in order to obtain sufficient choline for ACh synthesis and the continued function of cholinergic neurons, a breakdown of membrane phosphatidyl choline is required leading to cell death (so-called autocannibalism), /i-amyloid can also reduce the secondary effects of Mi receptor activation such as GTPase activity... 

There is evidence that in cerebral ischaemia adenosine may have protective effects, since it inhibits the release of many excitatory neurotransmitters, such as glutamate, and it also stabilises the membrane potential. Unfortunately, adenosine has an extremely short half-life, but recently nucleoside (adenosine) transport inhibitors, e.g. draflazine, have been developed that prevent the endothelial uptake and breakdown of adenosine and prolong its beneficial effects. Nucleoside transport inhibitors also have myocardial protective properties and may have a role in organ preservation prior to transplantation. Adenosine also has an antinociceptive function and various adenosine analogues have antinociceptive activity, which correlates with their affinity for the A1 receptors (Lipkowski and co-workers 1996). 

Fig. 4.3 Uptake of glutamate is associated with ion transport across neural membranes. Ion transport results in entry of 3 sodium ions and 1 proton in the cell whilst 1 potassium ion is transported out (modified from Attwell, 2000)...

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