Effects of 6-hydroxydopamine on oxidative phosphorylation of mitochondria from rat striatum, cortex, and liver

1988 ◽  
Vol 66 (3) ◽  
pp. 376-379 ◽  
Author(s):  
J. H. Thakar ◽  
M. N. Hassan
Keyword(s):  
Oxidative Phosphorylation ◽  
Incubation Medium ◽  
Respiratory Control ◽  
Rat Striatum ◽  
Respiratory Control Ratio ◽  
Chemical Sympathectomy ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Consumption Ratio ◽  
6 Hydroxydopamine

The catecholamine neurotoxin 6-hydroxydopamine (6-OHDA) has been used to produce cardiac chemical sympathectomy as well as a model of parkinsonism. Several mechanisms have been proposed to explain its cytotoxicity, including the productions of quinones, hydrogen peroxide, and free radicals by autooxidation and the uncoupling of mitochondrial oxidative phosphorylation. We have observed that 6-OHDA at a concentration of 0.05 mM rapidly consumes oxygen from the mitochondrial incubation medium but does not affect oxidative phosphorylation in the mitochondria from rat striatum, cortex, and liver. At the higher concentration of 0.5 mM, 6-OHDA consumes all of the available oxygen from the incubation medium. Mitochondria exposed to this concentration of 6-OHDA show decreases in the respiratory control ratio and adenosine triphosphate synthesis as measured by the consumption ratio of ADP to oxygen. Thus, only the higher (0.5 mM) concentration of 6-OHDA, which produces anoxia in vitro, also causes mitochondrial damage.

Pseudomonas aeruginosa lipopolysaccharide: an uncoupler of mitochondrial oxidative phosphorylation

1975 ◽  
Vol 21 (6) ◽  
pp. 877-883 ◽  
Author(s):  
G. Gordon Greer ◽  
F. H. Milazzo
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Oxygen Uptake ◽  
Oxidative Phosphorylation ◽  
Respiratory Control ◽  
Substrate Oxidation ◽  
Respiratory Control Ratio ◽  
Mitochondrial Oxidative Phosphorylation

The addition of Pseudomonas aeruginosa KCIIR LPS to respiring mitochondria stimulated the rate of substrate oxidation, reduced the respiratory control ratio, stimulated oxygen uptake in state 4, and released the inhibition imposed upon state 3 by atractyloside. It was concluded that LPS acted as an uncoupler of oxidative phosphorylation and that it produced effects similar to those observed with the classical uncoupler 2,4-dinitrophenol.

Impairment of mitochondrial oxidative phosphorylation in skin fibroblasts of SALS and FALS patients is rescued by in vitro treatment with ROS scavengers

2021 ◽  
Vol 339 ◽  
pp. 113620
Author(s):  
Grazyna Debska-Vielhaber ◽  
Irina Miller ◽  
Viktoriya Peeva ◽  
Werner Zuschratter ◽  
Jaroslaw Walczak ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Skin Fibroblasts ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Ros Scavengers ◽  
In Vitro Treatment

scholarly journals Let-7a regulates EV secretion and mitochondrial oxidative phosphorylation by targeting SNAP23 in colorectal cancer

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
You Dong Liu ◽  
Xiao Peng Zhuang ◽  
Dong Lan Cai ◽  
Can Cao ◽  
Qi Sheng Gu ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Metabolic Reprogramming ◽  
Luciferase Reporter ◽  
Mitochondrial Oxidative Phosphorylation ◽  
In Vivo Assays ◽  
Reporter Assays ◽  
Extracellular Mirna

Abstract Background MicroRNAs (miRNAs) are abundant in tumor-derived extracellular vesicles (EVs) and the functions of extracellular miRNA to recipient cells have been extensively studied with tumorigenesis. However, the role of miRNA in EV secretion from cancer cells remains unknown. Methods qPCR and bioinformatics analysis were applied for determining extracellular let-7a expression from CRC patient serum and cells. Nanosight particle tracking analysis was performed for investigating the effect of let-7a on EV secretion. Luciferase reporter assays was used for identifying targeted genes synaptosome-associated protein 23 (SNAP23). In vitro and in vivo assays were used for exploring the function of let-7a/SNAP23 axis in CRC progression. Bioenergetic assays were performed for investigating the role of let-7a/SNAP23 in cellular metabolic reprogramming. Results let-7a miRNA was elevated in serum EVs from CRC patients and was enriched in CRC cell-derived EVs. We determined that let-7a could suppress EV secretion directly targeting SNAP23. In turn, SNAP23 promotes EV secretion of let-7a to downregulate the intracellular let-7a expression. In addition, we found a novel mechanism of let-7a/SNAP23 axis by regulating mitochondrial oxidative phosphorylation (OXPHOS) through Lin28a/SDHA signaling pathway. Conclusions Let-7a plays an essential role in not only inhibiting EV secretion, but also suppressing OXPHOS through SNAP23, resulting in the suppression of CRC progression, suggesting that let-7a/SNAP23 axis could provide not only effective tumor biomarkers but also novel targets for tumor therapeutic strategies.

scholarly journals Effects of Agents Used in the Pharmacotherapy of Cerebrovascular Disease on the Oxygen Consumption of Isolated Cerebral Mitochondria

1982 ◽  
Vol 2 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Jean-Pierre Nowicki ◽  
Eric T. MacKenzie ◽  
Brigitte Spinnewyn
Keyword(s):  
Energy Supply ◽  
Therapeutic Potential ◽  
Cerebrovascular Disorders ◽  
Respiratory Control ◽  
Base Line ◽  
Respiratory Control Ratio ◽  
Respiration Of Mitochondria ◽  
Considerable Body ◽  
The Brain

A number of drugs used in the pharmacotherapy of cerebral metabolic and vascular disease have been studied for their effects on the respiration of mitochondria isolated from the rat brain. Some of these agents increased the respiratory control ratio by more than 5% from base-line values (at p < 0.05), namely, aminophylline, dihydroergotoxine, ifenprodil, nicergoline, raubasine, and vincamine. The ability of these agents to increase the efficiency of mitochondrial respiration could be correlated with two other attributes peculiar to these five drugs: their ability to contract cerebrovascular smooth muscle when studied in vitro and their ability to decrease the volume of infarcted brain tissue following experimental occlusion of the middle cerebral artery in the cat. Papaverine and its derivatives (naftidrofuryl, viquidil, YC-93) decreased respiratory control, an effect that might correlate with their capacity to effect a vasodilatation of the cerebral vessels and their inefficacy in models of acute cerebral infarction. There is a considerable body of evidence suggesting that one of the earliest and most fundamental perturbations of cerebral ischaemia is a loss of respiratory control. Ifenprodil, vincamine, and some related “anti-ischaemic” compounds are capable of increasing respiratory control in normal cerebral mitochondria, and this capacity might well help to explain their therapeutic potential in cerebrovascular disorders in which energy supply to the brain is limited.

scholarly journals The effect of sulodexide on placental mitochondria function in rats with experimental preeclampsia

2016 ◽  
Vol 62 (5) ◽  
pp. 572-576 ◽  
Author(s):  
T.A. Popova ◽  
V.N. Perfilova ◽  
G.A. Zhakupova ◽  
V.E. Verovsky ◽  
O.V. Ostrovskij ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Mitochondrial Dysfunction ◽  
Respiratory Control ◽  
Negative Control ◽  
Urinary Protein ◽  
Control Group ◽  
Respiratory Control Ratio ◽  
Pregnant Rats ◽  
Pronounced Increase ◽  
Uncoupling Of Oxidative Phosphorylation

Substitution of drinking water for 1.8% NaCl in pregnant rats caused a pronounced increase in arterial pressure by 24,3% and urinary protein by 117% to day 21 of pregnancy. State 4 respiration of isolated placental mitochondria in the group of negative control was 3- and 1.5-fold higher with malate/glutamate and succinate as substrates than in placental mitochondria isolated from uncomplicated pregnant animals. This led to a decrease of the respiratory control ratio. These results suggest that development of experimental preeclampsia is accompanied by mitochondrial dysfunction through uncoupling of oxidative phosphorylation. Daily administration of sulodexide to females with experimental preeclampsia (EP) per os at a dose of 30 LE during the whole period of gestation decreased manifestations of the disease as evidenced by a slight increase in blood pressure (by 8,6%) and less pronounces increase in urinary protein (by 58,9%). Sulodexide decreased development of mitochondrial dysfunction in EP rats as shown a decrease of non-stimulated ADP respiration with malate/glutamate and succinate (4.5- and 2.5-fold, respectively) as compared with the negative control group and the corresponding increase in the respiratory control ratio (2.5- and 1.5-fold, respectively). Thus, sulodexide reduces uncoupling of oxidative phosphorylation and enhances the functional activity of mitochondria in EP animals, possibly due to its antioxidant and endotelioprotective effects.

scholarly journals Studies on valinomycin inhibition of synaptosome-fraction protein synthesis

1981 ◽  
Vol 196 (1) ◽  
pp. 25-32 ◽  
Author(s):  
M A Verity ◽  
M K Cheung ◽  
W J Brown
Keyword(s):  
Protein Synthesis ◽  
Respiratory Control ◽  
Microsomal Protein ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Subsequent Decrease ◽  
High K ◽  
Rapid Fall ◽  
Inhibition Of Protein Synthesis ◽  
External K

The ionophore valinomycin inhibited adult and neonatal synaptosome fraction protein synthesis with half-maximal inhibition at approximately 10nM. Valinomycin had no effect on [3H]leucine uptake into synaptosomes at high or low external [K+]. Synaptosome-fraction protein synthesis was dependent on [K+]e reaching a maximum at 25mM-K+. Valinomycin inhibition of protein synthesis was not reversed at high [K+]e. Valinomycin failed to influence the intrasynaptosomal [K+] even at zero [K+]e. A significant increase in State-4 respiration of synaptosomal fractions was found at 5nM-valinomycin with a decrease in the respiratory control index. At these concentrations of valinomycin there was no inhibition of the ADP-stimulated (State 3) respiration rate. Valinomycin had no effect on cerebral microsomal protein synthesis in vitro, which was inhibited by puromycin (100 micrograms/ml) or the absence of ATP. Valinomycin, 2,4-dinitrophenol and KCN inhibition of protein synthesis was not reversed by added ATP, suggesting impermeability of the membrane to ATP. Valinomycin induced a rapid fall in synaptosome ATP content not observed with atractylate or ouabain. Valinomycin inhibition of protein synthesis under these conditions is secondary to uncoupling of mitochondrial oxidative phosphorylation with a subsequent decrease in intraterminal ATP necessary for translation.

scholarly journals Preparation of rat enterocyte mitochondria

1984 ◽  
Vol 218 (2) ◽  
pp. 441-447 ◽  
Author(s):  
B Masola ◽  
D F Evered
Keyword(s):  
Cytochrome C ◽  
Oxidative Phosphorylation ◽  
Incubation Medium ◽  
Respiratory Control ◽  
Mitochondrial Fraction ◽  
Marker Enzymes ◽  
Cell Organelles ◽  
Succinate Dehydrogenase Activity ◽  
Isolation Medium ◽  
Mitochondrial Preparation

Rat enterocyte mitochondria were prepared with respiratory control ratios of 4 or 5 and occasionally 6. When EGTA was excluded from the mitochondrial incubation medium the calculated P/O ratios were high, especially those based on the first addition of ADP. These ratios were lowered by increasing the EGTA concentration from 1 mM to 2 mM in the mitochondrial preparation medium and including 1 mM-EGTA in the incubation medium. The use of EDTA in the enterocyte isolation medium led to the mitochondria requiring added cytochrome c. Substituting EGTA for EDTA abolished this requirement. The mitochondrial fraction consisted of two components, an upper cream-coloured layer rich in DNA and a lower brown-coloured layer poor in DNA. Both components were capable of oxidative phosphorylation with succinate or the glutamate/malate couple as substrates. The mitochondrial yield was assessed by assaying succinate dehydrogenase activity, and the contamination of the mitochondrial fraction by other cell organelles was assessed by assays for appropriate marker enzymes.

scholarly journals Skeletal muscle mitochondrial oxidative phosphorylation function in idiopathic pulmonary arterial hypertension: in vivo and in vitro study

2018 ◽  
Vol 8 (2) ◽  
pp. 204589401876829 ◽  
Author(s):  
Sasiharan Sithamparanathan ◽  
Mariana C. Rocha ◽  
Jehill D. Parikh ◽  
Karolina A. Rygiel ◽  
Gavin Falkous ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Pulmonary Arterial Hypertension ◽  
Oxidative Phosphorylation ◽  
Arterial Hypertension ◽  
Idiopathic Pulmonary Arterial Hypertension ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Pulmonary Vessels ◽  
Pulmonary Arterial

Mitochondrial dysfunction within the pulmonary vessels has been shown to contribute to the pathology of idiopathic pulmonary arterial hypertension (IPAH). We investigated the hypothesis of whether impaired exercise capacity observed in IPAH patients is in part due to primary mitochondrial oxidative phosphorylation (OXPHOS) dysfunction in skeletal muscle. This could lead to potentially new avenues of treatment beyond targeting the pulmonary vessels. Nine clinically stable participants with IPAH underwent cardiopulmonary exercise testing, in vivo and in vitro assessment of mitochondrial function by 31P-magnetic resonance spectroscopy (31P-MRS) and laboratory muscle biopsy analysis. 31P-MRS showed abnormal skeletal muscle bioenergetics with prolonged recovery times of phosphocreatine and abnormal muscle pH handling. Histochemistry and quadruple immunofluorescence performed on muscle biopsies showed normal function and subunit protein abundance of the complexes within the OXPHOS system. Our findings suggest that there is no primary mitochondrial OXPHOS dysfunction but raises the possibility of impaired oxygen delivery to the mitochondria affecting skeletal muscle bioenergetics during exercise.

Respiration and oxidative phosphorylation by muscle and heart mitochondria of hamsters with hereditary myocardiopathy and polymyopathy

1968 ◽  
Vol 46 (4) ◽  
pp. 323-329 ◽  
Author(s):  
Klaus Wrogemann ◽  
M. C. Blanchaer
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Histological Examination ◽  
Creatine Phosphokinase ◽  
Respiratory Control ◽  
Isolation Procedure ◽  
Heart Mitochondria ◽  
Respiratory Control Ratio ◽  
Skeletal Muscle Mitochondria ◽  
Serum Creatine Phosphokinase

Mitochondria isolated from skeletal muscle and heart of normal Syrian hamsters and from hamsters of the BIO 14.6 myopathic strain aged 97–124 days were studied. Histological examination of the tissues and serum creatine phosphokinase determinations established that the disease was active in the dystrophic animals. In the mitochondrial isolation procedure the minced tissue was incubated before homogenization in a mannitol–sucrose–EDTA medium containing a proteinase (Nagarse). Polarographic estimations with pyruvate–malate as substrate, in the presence and absence of ADP, indicated that the rate of O2 uptake, ADP/O ratio, and respiratory control ratio (state 3 to 4 transition) of the heart mitochondria did not suffer significantly between the normal and myopathic groups. The findings with the skeletal muscle mitochondria were similar. L-α-Glycerophosphate oxidation also was not affected by the myopathy but the rate of NADH oxidation was 35% slower in the heart mitochondria of the BIO 14.6 strain.

Ketamine: evidence of tissue specific inhibition of neuronal and extraneuronal catecholamine uptake processes

1985 ◽  
Vol 63 (4) ◽  
pp. 298-303 ◽  
Author(s):  
Paul M. Lundy ◽  
Sharunas Gverzdys ◽  
Robert Frew
Keyword(s):  
Mechanism Of Action ◽  
Rabbit Aorta ◽  
Adrenergic Innervation ◽  
Extraneuronal Uptake ◽  
Specific Inhibition ◽  
Chemical Sympathectomy ◽  
Rat Anococcygeus Muscle ◽  
Extraneuronal Catecholamine Uptake ◽  
6 Hydroxydopamine

Ketamine (1.1 × 10−5 to 3.7 × 10−4 M) potentiated catecholamine responses of rat anococcygeus muscle and rabbit aorta in vitro. In the anococcygeus, potentiation was abolished by cocaine (2.9 × 10−5 M) pretreatment or by chemical sympathectomy using 6-hydroxydopamine (6-OHDA), but was unaffected by pretreatment with the extraneuronal uptake inhibitor cortisol (8.3 × 10−5 M), or the catechol-O-methyltransferase inhibitor tropolone (2.4 × 10−4 M). The action of ketamine mimicked the potentiating effect of cocaine on tyramine responses. In contrast, the potentiation by ketamine in rabbit aorta was unaffected by cocaine or 6-OHDA but was abolished by cortisol or tropolone; and ketamine potentiated tyramine responses, whereas cocaine inhibited them. Thus the mechanism of action by which ketamine produces potentiation of catecholamines in these two tissues is completely different. These results suggest that ketamine has the unusual ability to block neuronal and extraneuronal uptake and that the predominating mechanism will depend on the type of tissue examined and the morphology of its adrenergic innervation.

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