scholarly journals Glutamate and aspartate transport in rat brain mitochondria

1974 ◽  
Vol 140 (2) ◽  
pp. 205-210 ◽  
Author(s):  
M. D. Brand ◽  
J. B. Chappell
Keyword(s):  
Rat Brain ◽  
Mitochondrial Membrane ◽  
Liver Mitochondria ◽  
Brain Mitochondria ◽  
Kidney Mitochondria ◽  
Pig Kidney ◽  
Rat Brain Mitochondria ◽  
Energy Dependent ◽  
Glutaminase Activity ◽  
Malate Aspartate Shuttle

1. Rat brain mitochondria did not swell in iso-osmotic solutions of ammonium or potassium (plus valinomycin) glutamate or aspartate, with or without addition of uncouplers. 2. Glutamate was able to reduce intramitochondrial NAD(P)+; aspartate was able to cause partial re-oxidation. 3. These effects were inhibited by threo-hydroxy-aspartate in whole but not in lysed mitochondria. 4. The existence of a ‘malate–aspartate shuttle’ for the oxidation of extramitochondrial NADH was demonstrated. This shuttle requires the net exchange of glutamate for aspartate across the mitochondrial membrane. 5. Extramitochondrial glutamate did not inhibit intramitochondrial glutaminase under conditions in which the inhibition in lysed mitochondria was virtually complete. 6. The glutaminase activity of these mitochondria was not energy-dependent. 7. We conclude that these mitochondria do not possess a glutamate–hydroxyl antiporter similar to that of liver mitochondria nor a glutamate–glutamine antiporter similar to that of pig kidney mitochondria, but that they do possess a glutamate–aspartate antiporter.

THE UPTAKE OF GLYCINE BY RAT BRAIN MITOCHONDRIA

1965 ◽  
Vol 43 (7) ◽  
pp. 1119-1127 ◽  
Author(s):  
T. Nukada
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Structural Integrity ◽  
Brain Mitochondria ◽  
Sodium Ions ◽  
Glycine Uptake ◽  
Kidney Mitochondria ◽  
Rat Brain Mitochondria ◽  
Sodium Dependent

Rat brain mitochondrial pellets are able to accumulate glycine by a sodium-dependent and ouabain-sensitive process which is not potassium dependent. This process does not occur in liver or kidney mitochondria. Glycine uptake by brain mitochondria is not affected by the addition of ATP, NAD, or other cofactors, but it is inhibited by dinitrophenol and, competitively, by certain amino acids. Data obtained by the use of various concentrations of sodium ions or of sucrose indicate that the uptake of glycine by brain mitochondria is closely linked with their structural integrity.

scholarly journals Glutamate metabolism and transport in rat brain mitochondria

1976 ◽  
Vol 156 (2) ◽  
pp. 323-331 ◽  
Author(s):  
S C Dennis ◽  
J M Land ◽  
J B Clark
Keyword(s):  
Rat Brain ◽  
Glutamate Uptake ◽  
Liver Mitochondria ◽  
Brain Mitochondria ◽  
Glutamate Metabolism ◽  
Rat Brain Mitochondria

1. The metabolism and transport of glutamate and glutamine in rat brain mitochondria of non-synaptic origin has been studied in various states. 2. These mitochondria exhibited glutamate uptake and swelling in iso-osmotic ammonium glutamate, both of which were inhibited by N-ethylmaleimide. 3. The oxidation of glutamate was inhibited by 20% by avenaciolide, but glutamine oxidation was not affected. 4. These mitochondria, when metabolizing glutamine, allowed glutamate, but very little aspartate, to efflux at considerable rates. 5. These results suggests that brain mitochondria of non-synaptic origin possess in addition to a relatively rapid glutamate-aspartate translocase, a relatively slow aspartate-independent glutamate-OH-translocase (cf. liver mitochondria).

Ca2+-dependent permeability transition regulation in rat brain mitochondria by 2′,3′-cyclic nucleotides and 2′,3′-cyclic nucleotide 3′-phosphodiesterase

2009 ◽  
Vol 296 (6) ◽  
pp. C1428-C1439 ◽  
Author(s):  
Tamara Azarashvili ◽  
Olga Krestinina ◽  
Anastasia Galvita ◽  
Dmitry Grachev ◽  
Yulia Baburina ◽  
...  
Keyword(s):  
Rat Brain ◽  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Brain Mitochondria ◽  
Rat Liver Mitochondria ◽  
Marker Enzyme ◽  
Rat Brain Mitochondria ◽  
Specific Enzymatic Activity

Recent evidence indicates that 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP), a marker enzyme of myelin and oligodendrocytes, is also present in neural and nonneural mitochondria. However, its role in mitochondria is still completely unclear. We found CNP in rat brain mitochondria and studied the effects of CNP substrates, 2′,3′-cyclic nucleotides, on functional parameters of rat brain mitochondria. 2′,3′-cAMP and 2′,3′-cNADP stimulated Ca2+ overload-induced Ca2+ release from mitochondrial matrix. This Ca2+ release under threshold Ca2+ load correlated with membrane potential dissipation and mitochondrial swelling. The effects of 2′,3′-cyclic nucleotides were suppressed by cyclosporin A, a potent inhibitor of permeability transition (PT). PT development is a key stage in initiation of apoptotic mitochondria-induced cell death. 2′,3′-cAMP effects were observed on the functions of rat brain mitochondria only when PT was developed. This demonstrates involvement of 2′,3′-cAMP in PT regulation in rat brain mitochondria. We also discovered that, under PT development, the specific enzymatic activity of CNP was reduced. Thus we hypothesize that suppression of CNP activity under threshold Ca2+ load leads to elevation of 2′,3′-cAMP levels that, in turn, promote PT development in rat brain mitochondria. Similar effects of 2′,3′-cyclic nucleotides were observed in rat liver mitochondria. Involvement of CNP in PT regulation was confirmed in experiments using mitochondria from CNP-knockdown oligodendrocytes (OLN93 cells). CNP reduction in these mitochondria correlated with lowering the threshold for Ca2+ overload-induced Ca2+ release. Thus our results reveal a new function for CNP and 2′,3′-cAMP in mitochondria, being a regulator/promotor of mitochondrial PT.

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