Glutamate Release by Reversed Glutamate Uptake Is Inhibited by Arachidonic Acid
Glutamate uptake into neurones and glia helps to terminate the synaptic action of neurotransmitter glutamate and to keep the extracellular glutamate concentration below levels which are neurotoxic. Recently we have shown  that glutamate uptake into glial cells can be monitored as a membrane current using whole-cell patch clamping. This technique depends on the fact that the glutamate uptake carrier transports a net positive charge into the cell on each carrier cycle: the carrier is thought to transport three sodium ions (or possibly two Na+ and one proton ) into the cell with each glutamate anion, and to transport one potassium ion out of the cell . Using whole-cell patch clamping to study glutamate uptake allows uptake to be studied under voltage-clamp conditions (which is important because membrane potential is a crucial determinant of the rate of uptake ) and allows the composition of the cell contents to be controlled via the patch pipette (a facility which is employed in the experiments reported below).
KeywordsIschemia Albumin Retina Barium NMDA
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- 2.Szatkowski M, Barbour B, Attwell D (1991) Glutamate uptake in glial cells isolated from the salamander retina generates an extracellular alkalinization and an intracellular acidification. J Physiol (Lond) 438: 261 PGoogle Scholar
- 6.Miller B, Sarantis M, Attwell D (1991) Effects of arachidonic acid on glutamate-gated channels in granule cells cultured from rat cerebellum. J Physiol (Lond) (in press)Google Scholar
- 7.Barbour B, Szatkowski M, Ingledew N, Attwell D (1989) Arachidonic acid induces a prolonged inhibition of glutamate uptake into glial cells. Nature 342: 918920Google Scholar
- 11.Kauppinen RA, McMahon HT, Nicholls DG (1988) Cat+-dependent and CaZ+-independent glutamate release, energy status and cytosolic free CaZ+ concentration in isolated nerve terminals following metabolic inhibition: possible relevance to hypoglycaemia and anoxia. Neuroscience 27: 175–182PubMedCrossRefGoogle Scholar
- 12.Barbour B, Brew H, Attwell D (1991) Electrogenic uptake of glutamate and aspartate into glial cells isolated from the salamander (Ambystoma) retina. J Physiol (Lond) 436: 169–193Google Scholar