Neuron-glia interactions in glutamatergic neurotransmission: roles of oxidative and glycolytic adenosine triphosphate as energy source

TY - JOUR

T1 - Neuron-glia interactions in glutamatergic neurotransmission

T2 - roles of oxidative and glycolytic adenosine triphosphate as energy source

AU - Schousboe, A

AU - Sickmann, H M

AU - Bak, Lasse Kristoffer

AU - Schousboe, I

AU - Jajo, F S

AU - Faek, S A A

AU - Waagepetersen, H S

N1 - Copyright © 2011 Wiley-Liss, Inc.

PY - 2011/12/1

Y1 - 2011/12/1

N2 - Glutamatergic neurotransmission accounts for a considerable part of energy consumption related to signaling in the brain. Chemical energy is provided by adenosine triphosphate (ATP) formed in glycolysis and tricarboxylic acid (TCA) cycle combined with oxidative phosphorylation. It is not clear whether ATP generated in these pathways is equivalent in relation to fueling of the energy-requiring processes, i.e., vesicle filling, transport, and enzymatic processing in the glutamatergic tripartite synapse (the astrocyte and pre- and postsynapse). The role of astrocytic glycogenolysis in maintaining theses processes also has not been fully elucidated. Cultured astrocytes and neurons were utilized to monitor these processes related to glutamatergic neurotransmission. Inhibitors of glycolysis and TCA cycle in combination with pathway-selective substrates were used to study glutamate uptake and release monitored with D-aspartate. Western blotting of glyceraldehyde-3-P dehydrogenase (GAPDH) and phosphoglycerate kinase (PGK) was performed to determine whether these enzymes are associated with the cell membrane. We show that ATP formed in glycolysis is superior to that generated by oxidative phosphorylation in providing energy for glutamate uptake both in astrocytes and in neurons. The neuronal vesicular glutamate release was less dependent on glycolytic ATP. Dependence of glutamate uptake on glycolytic ATP may be at least partially explained by a close association in the membrane of GAPDH and PGK and the glutamate transporters. It may be suggested that these enzymes form a complex with the transporters and the Na +/K +-ATPase, the latter providing the sodium gradient required for the transport process.

AB - Glutamatergic neurotransmission accounts for a considerable part of energy consumption related to signaling in the brain. Chemical energy is provided by adenosine triphosphate (ATP) formed in glycolysis and tricarboxylic acid (TCA) cycle combined with oxidative phosphorylation. It is not clear whether ATP generated in these pathways is equivalent in relation to fueling of the energy-requiring processes, i.e., vesicle filling, transport, and enzymatic processing in the glutamatergic tripartite synapse (the astrocyte and pre- and postsynapse). The role of astrocytic glycogenolysis in maintaining theses processes also has not been fully elucidated. Cultured astrocytes and neurons were utilized to monitor these processes related to glutamatergic neurotransmission. Inhibitors of glycolysis and TCA cycle in combination with pathway-selective substrates were used to study glutamate uptake and release monitored with D-aspartate. Western blotting of glyceraldehyde-3-P dehydrogenase (GAPDH) and phosphoglycerate kinase (PGK) was performed to determine whether these enzymes are associated with the cell membrane. We show that ATP formed in glycolysis is superior to that generated by oxidative phosphorylation in providing energy for glutamate uptake both in astrocytes and in neurons. The neuronal vesicular glutamate release was less dependent on glycolytic ATP. Dependence of glutamate uptake on glycolytic ATP may be at least partially explained by a close association in the membrane of GAPDH and PGK and the glutamate transporters. It may be suggested that these enzymes form a complex with the transporters and the Na +/K +-ATPase, the latter providing the sodium gradient required for the transport process.

KW - Former Faculty of Pharmaceutical Sciences

U2 - 10.1002/jnr.22746

DO - 10.1002/jnr.22746

M3 - Journal article

C2 - 21919035

SN - 0360-4012

VL - 89

SP - 1926

EP - 1934

JO - Journal of Neuroscience Research

JF - Journal of Neuroscience Research

IS - 12

ER -