Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glutamate (Glu) immunocytochemistry has been widely used to identify presumed gluergic neurons and synapses, but several problems related to the fact that Glu is both a synaptic transmitter and a compound used for metabolic purposes are still unsolved. One of these concerns the intense perikaryal staining observed in perfusion-fixed tissue. Phosphate-activated glutaminase, a key enzyme for the synthesis of releasable glutamate, is inhibited by the diazoketone 6-diazo-5-oxo-L-norleucine (DON), which greatly reduces glutamate release. In the present experiments, DON was either injected intraparenchymally or applied epipially to the sensorimotor cortex of adult Sprague-Dawley rats at concentrations of 0.25-1 mM. Both intraparenchymal and epipial applications of the chemical abolished Glu immunoreactivity in neuron perikarya. Adjacent sections processed for cytochrome oxidase histochemistry, for aspartate immunoreactivity, or stained with thionine showed no changes. The effects of DON application are reversible, as shown in a second series of experiments in which, after 30 min of DON application, animals were allowed to survive for 5-10 days. In these cases, Glu immunoreactivity in cortical neurons was identical to that observed in normal untreated animals. The results reported here suggest that Glu immunoreactivity demonstrated by the present procedure in neuron perikarya is mainly due to Glu produced via phosphate-activated glutaminase.
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PMID:Glutamate immunoreactivity in rat cerebral cortex is reversibly abolished by 6-diazo-5-oxo-L-norleucine (DON), an inhibitor of phosphate-activated glutaminase. 791 Jun 17

Sporadic Amyotrophic Lateral Sclerosis (SALS) is a fatal neurologic disease characterized by degeneration of motor neurons in the spinal cord, brainstem and cortex. While familial cases of ALS exist, the sporadic form accounts for the majority of adult-onset cases. It has been hypothesized that the neurodegenerative mechanisms underlying SALS might arise from glutamate-mediated excitotoxicity and mitochondrial dysfunction. Studies on autopsied SALS spinal cord and brain have reported decreased cytochrome oxidase activity, decreased astrocytic glutamate-transporter protein, and alterations of glutamate levels and glutamate metabolizing enzyme activities. We conjectured that if alterations in glutamate metabolism and cytochrome oxidase activity occur in the SALS central nervous system these alterations may also be manifested in peripheral tissues such as platelets in living SALS patients. In this study we compared the activities of cytochrome oxidase, citrate synthase, glutamate dehydrogenase and glutaminase in platelets from SALS and control subjects. We found that there were no differences in any of the enzyme activities measured between the two groups. Our data argue against generalized ubiquitous biochemical alterations of these enzymes in SALS patients.
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PMID:Unaltered cytochrome oxidase, glutamate dehydrogenase and glutaminase activities in platelets from patients with sporadic amyotrophic lateral sclerosis--a study of potential pathogenetic mechanisms in neurodegenerative diseases. 1145 96

Oophorectomy in adult rats affected cardiac mitochondrial function. Progression of mitochondrial alterations was assessed at one, two and three months after surgery: at one month, very slight changes were observed, which increased at two and three months. Gradual effects included decrease in the rates of oxygen consumption and in respiratory uncoupling in the presence of complex I substrates, as well as compromised Ca2+ buffering ability. Malondialdehyde concentration increased, whereas the ROS-detoxifying enzyme Mn2+ superoxide dismutase (MnSOD) and aconitase lost activity. In the mitochondrial respiratory chain, the concentration and activity of complex I and complex IV decreased. Among other mitochondrial enzymes and transporters, adenine nucleotide carrier and glutaminase decreased. 2-Oxoglutarate dehydrogenase and pyruvate dehydrogenase also decreased. Data strongly suggest that in the female rat heart, estrogen depletion leads to progressive, severe mitochondrial dysfunction.
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PMID:In female rat heart mitochondria, oophorectomy results in loss of oxidative phosphorylation. 2787 98