Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phosphate-activated glutaminase, glutamic acid decarboxylase, pyruvate dehydrogenase, succinic dehydrogenase, pH, and lactate were measured in frontal cortex and caudate nucleus of postmortem brains from cases of Alzheimer-type dementia (ATD), Down's syndrome, Huntington's disease, and one case of Pick's disease, as well as from sudden death and agonal controls. Lactate levels were higher and pH, phosphate-activated glutaminase, and glutamic acid decarboxylase levels were lower in the agonal controls than in the sudden death controls. Phosphate-activated glutaminase and glutamic acid decarboxylase were correlated with tissue pH and lactate, and also were reduced by in vitro acidification, suggesting that the low activities of these enzymes in agonal controls were related to decreased pH consequent upon lactate accumulation. Compared with control tissues at the same pH, phosphate-activated glutaminase and glutamic acid decarboxylase were unaltered in ATD and Down's frontal cortex and reduced in Huntington's caudate nucleus, and glutamic acid decarboxylase was reduced in Huntington's frontal cortex. These data suggest that GABAergic neurons are not affected in ATD and confirm the GABAergic defect in Huntington's disease. Pyruvate dehydrogenase and succinic dehydrogenase activities were the same in agonal controls and sudden death controls and were unaffected by acid pH and lactate in vitro, and pyruvate dehydrogenase was not correlated with pH or lactate. Reduced pyruvate dehydrogenase in frontal cortex of individual ATD, Down's, and Pick's cases, and in the caudate nucleus of Huntington's and Down's cases, was accompanied by gliosis/neuron loss. We conclude that decreased pyruvate dehydrogenase reflects neuronal loss.
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PMID:Enzyme activities in relation to pH and lactate in postmortem brain in Alzheimer-type and other dementias. 221 15

The activity of phosphate-activated glutaminase was reduced throughout the brain of cases with longstanding illnesses (agonal controls) compared to cases dying suddenly. The reduction was less marked in cortical than sub-cortical areas, with the caudate nucleus occupying an intermediate position. In control brains succinic dehydrogenase and pyruvate dehydrogenase were little affected by the ante-mortem clinical state. Of 9 brain areas studied, only the caudate nucleus showed a reduction of phosphate-activated glutaminase and succinic dehydrogenase in Huntington's disease greater than in agonal controls. The levels of succinic dehydrogenase and pyruvate dehydrogenase were highly correlated in frontal cortex and in caudate nucleus of Huntington's disease and control brains. There was a significant reduction in pyruvate dehydrogenase mean activity and a significant increase in gamma-glutamyl transpeptidase mean activity in Huntington's disease caudate nucleus. The level of pyruvate dehydrogenase significantly decreased and the level of gamma-glutamyl transpeptidase significantly increased with increasing duration of illness, possibly due to a progressive loss of neurons and increase in the density of glia in Huntington's disease caudate nucleus.
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PMID:Distribution of phosphate-activated glutaminase, succinic dehydrogenase, pyruvate dehydrogenase and gamma-glutamyl transpeptidase in post-mortem brain from Huntington's disease and agonal cases. 285 15

Involvement of phosphate-activated glutaminase in Huntington's disease and agonal state was investigated in caudate nucleus and frontal cortex from postmortem brains. In Huntington's disease the activities of phosphate-activated glutaminase, glutamic acid decarboxylase, succinic dehydrogenase, choline acetyltransferase, and acetylcholinesterase were significantly reduced in the caudate nucleus, but not in the frontal cortex. The activity of phosphate-activated glutaminase, and to a lesser extent of glutamic acid decarboxylase, was reduced in cases of terminal illness, as compared with cases of sudden death. Succinic dehydrogenase and choline acetyltransferase were reduced only in the few cases of prolonged and severe terminal illness. Enzyme activities of the caudate nucleus were more affected by agonal state than were those of frontal cortex. Results indicate that phosphate-activated glutaminase could be a useful marker of neuronal damage due to agonal state, and that phosphate-activated glutaminase and succinic dehydrogenase are reduced in Huntington's disease.
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PMID:Phosphate-activated glutaminase in relation to Huntington's disease and agonal state. 622 89

Adult rats received chronic dialytic delivery devices that exposed the striatum to a 100 mM, 400 mM, or 4 M solution of the reversible succinate dehydrogenase inhibitor malonic acid (MA). Three weeks of exposure to 100 or 400 mM MA produced no significant reduction in striatal cytochrome oxidase staining, whereas striata chronically exposed to 1 and 4 M MA showed a significant and dose-related reduction in cytochrome oxidase staining. In striata exposed to 1 M MA, analysis of regions radial to the necrotic core revealed significant reduction of nissl cell staining with relative sparing of NADPH-diaphorase-containing neurons. Although 100 and 400 mM MA failed to produce lesions, both of these concentrations significantly decreased the number of striatal calbindin (CALB) immunoreactive perikarya. The reduction in CALB immunoreactivity was partly reversed in animals allowed to survive 4 weeks after cessation of exposure to 400 mM MA. These results indicate that, like striatal lesions produced by quinolinic acid, lesions produced by chronic exposure to MA possess a Huntington's disease-like pattern of selective neurodegeneration. In addition, exposure to subthreshold MA concentrations (100 and 400 mM) produce widespread transient changes in striatal CALB that may be associated with a premorbid state of neuronal dysfunction.
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PMID:Chronic administration of malonic acid produces selective neural degeneration and transient changes in calbindin immunoreactivity in rat striatum. 755 44

Although the gene defect responsible for Huntington disease (HD) has recently been identified, the pathogenesis of the disease remains obscure. One potential mechanism is that the gene defect may lead to an impairment of energy metabolism followed by slow excitotoxic neuronal injury. In the present study we examined whether chronic administration of 3-nitropropionic acid (3-NP), an irreversible inhibitor of succinate dehydrogenase, can replicate the neuropathologic and clinical features of HD in nonhuman primates. After 3-6 weeks of 3-NP administration, apomorphine treatment induced a significant increase in motor activity as compared with saline-treated controls. Animals showed both choreiform movements, as well as foot and limb dystonia, which are characteristic of HD. More prolonged 3-NP treatment in two additional primates resulted in spontaneous dystonia and dyskinesia accompanied by lesions in the caudate and putamen seen by magnetic resonance imaging. Histologic evaluation showed that there was a depletion of calbindin neurons, astrogliosis, sparing of NADPH-diaphorase neurons, and growth-related proliferative changes in dendrites of spiny neurons similar to changes in HD. The striosomal organization of the striatum and the nucleus accumbens were spared. These findings show that chronic administration of 3-NP to nonhuman primates can replicate many of the characteristic motor and histologic features of HD, further strengthening the possibility that a subtle impairment of energy metabolism may play a role in its pathogenesis.
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PMID:Chronic mitochondrial energy impairment produces selective striatal degeneration and abnormal choreiform movements in primates. 762 78

Intrastriatal injection of malonate, a reversible inhibitor of succinate dehydrogenase (SDH), produced age-dependent striatal lesions, which were significantly greater in 4- and 12-month-old animals than in 1-month-old animals. Both histologic and neurochemical studies showed that the lesions were significantly attenuated by administration of the noncompetitive NMDA receptor antagonist MK-801. Water-suppressed chemical shift magnetic resonance imaging showed that malonate produces increased striatal lactate concentrations and striatal lesions on T2-weighted scans that were attenuated by MK-801. Neurochemical characterization of the lesions showed significant decreases in markers of medium-sized spiny neurons (GABA and substance P), whereas a marker of medium-sized aspiny neurons (somatostatin) was not different from control values, consistent with an NMDA receptor-mediated mechanism. The effects of intrastriatal injections of malonate on ATP concentrations were compared with those of the irreversible SDH inhibitor 3-nitropropionic acid (3-NP). The ATP depletions following an equimolar injection of malonate were less marked and more transient than those of 3-NP. These results show that the competitive SDH inhibitor malonate produces more transient and milder bioenergetic defects than 3-NP, which are associated with selective activation of NMDA receptors. The results strengthen the possibility that a subtle impairment of energy metabolism may play a role in the pathogenesis of Huntington's disease.
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PMID:Age-dependent striatal excitotoxic lesions produced by the endogenous mitochondrial inhibitor malonate. 768 41

Huntington's disease (HD) is a prototypical neurodegenerative disease characterized by selective loss of neurons in the basal ganglia. Although the gene defect has recently been identified, the mechanism by which it leads to neuronal degeneration remains unknown. We have hypothesized that a defect in oxidative phosphorylation may lead to slow, excitotoxic neuronal degeneration in this illness. Evidence for such a defect is reviewed here, including our recent studies using magnetic resonance imaging spectroscopy that show elevated lactate levels in the basal ganglia and cerebral cortex of patients with HD. If a defect in energy metabolism is responsible for neuronal degeneration in HD, it should be possible to mimic the neurodegenerative process with mitochondrial toxins. Our recent studies with 3-nitropropionic acid, an irreversible inhibitor of succinate dehydrogenase, show that it can produce striking similarities to the neuropathologic and neurochemical features of HD in both rodents and primates. If such a mechanism is indeed relevant to the pathogenesis of HD, then agents that can improve oxidative phosphorylation might prove to be efficacious. We found that both coenzyme Q10 and nicotinamide can ameliorate striatal lesions produced by mitochondrial toxins in vivo. Furthermore, they reduced elevated lactate concentrations when administered to patients with HD. This finding raises the possibility that such an approach might prove useful in trying to slow the neurodegenerative process.
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PMID:Neurochemistry and toxin models in Huntington's disease. 786 87

A major theory regarding the mechanism of neuronal degeneration in several movement disorders is that mitochondrial defects may play a role. Biochemical studies in Parkinson's disease, Huntington's disease, multiple system atrophy, and idiopathic dystonia have shown defects in enzymes of oxidative phosphorylation in postmortem brain tissue, platelets, muscle, or lymphocytes. The basal ganglia and substantia nigra are also particularly susceptible to the accumulation of age-dependent mitochondrial DNA deletions, which may contribute to the delayed onset of movement disorders. The 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine model of Parkinson's disease involves conversion to 1-methyl-4-phenylpyridinium, which then inhibits complex I of the electron transport chain. Our studies show that the complex II inhibitor 3-nitropropionic acid can closely replicate the neurochemical, histologic, and clinical features of Huntington's disease. The mechanism of neuronal death in both these models may be slow excitotoxicity. Both direct biochemical studies and animal models of movement disorders therefore suggest that mitochondrial dysfunction may play a direct role in their pathogenesis.
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PMID:Mitochondrial dysfunction in movement disorders. 795 42

Consistent with the notion that a defect in cellular energy metabolism is a cause of human neurodegenerative disease, systemic treatment with the mitochondrial complex II inhibitor 3-nitropropionic acid (3-NPA) can model the striatal neurodegeneration seen in Huntington's disease. Previously, we have found that nerve growth factor (NGF), delivered biologically by the implantation of a genetically altered fibroblast cell-line, can protect locally against striatal degeneration induced by infusions of high doses of glutamate receptor agonists. We now report that implantation of NGF-secreting fibroblasts reduces the size of adjacent striatal 3-NPA lesions by an average of 64%. We conclude that biologically delivered NGF protects neurons against excitotoxicity and mitochondrial blockade--both energy-depleting processes--implying that appropriate neurotrophic support in the adult brain could protect against neurodegenerative diseases caused in part by energy depletion.
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PMID:Striatal degeneration induced by mitochondrial blockade is prevented by biologically delivered NGF. 810 16

Although the Huntington's disease (HD) gene defect has been identified, the structure and function of the abnormal gene product and the pathogenetic mechanisms involved in producing death of selective neuronal populations are not understood. Indirect evidence from several sources indicates that a defect of energy metabolism and consequent excitotoxicity are involved in HD. Toxin models of HD may be induced by 3-nitropropionic acid or malonate, both inhibitors of succinate dehydrogenase, complex II of the mitochondrial respiratory chain. We analyzed mitochondrial respiratory chain function in the caudate nucleus (n = 10) and platelets (n = 11) from patients with HD. In the caudate nucleus, severe defects of complexes II and III (53-59%, p < 0.0005) and a 32-38% (p < 0.01) deficiency of complex IV activity were demonstrated. No deficiencies were found in platelet mitochondrial function. The mitochondrial defect identified in HD caudate parallels that induced by HD neurotoxin models and further supports the role of abnormal energy metabolism in HD. The relationship of the mitochondrial defect to the role of huntingtin is not known.
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PMID:Mitochondrial defect in Huntington's disease caudate nucleus. 860 59


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