Examining Mitochondrial Function at Synapses In Situ

Author(s):  
Gregory T. Macleod ◽  
Maxim V. Ivannikov
1990 ◽  
Vol 259 (6) ◽  
pp. H1759-H1766 ◽  
Author(s):  
W. Rouslin ◽  
C. W. Broge ◽  
I. L. Grupp

In the present study, isolated dog and rat hearts were perfused in the Langendorff mode with Krebs bicarbonate buffer in the absence and presence of 10(-5) M oligomycin. The perfusion protocols employed allowed tissue pH to drop during subsequent ischemic incubations essentially as it would in blood-perfused hearts. Tissue pH, ATP, lactate, and mitochondrial respiratory function were measured during the course of subsequent zero-flow ischemic incubations. The adenosinetriphosphatase (ATPase) activities attributable to both mitochondrial and nonmitochondrial ATPases in sonicated heart homogenates and the actomyosin ATPase in isolated cardiac myofibrils were measured in both species. Consistent with earlier results with a different model in which tissue pH was buffered during the ischemic incubations [W. Rouslin, J. L. Erickson, and R. J. Solaro. Am. J. Physiol. 250 (Heart Circ. Physiol. 19): H503-H508, 1986], the inhibition of the mitochondrial ATPase in situ by oligomycin markedly slowed both tissue ATP depletion and the loss of mitochondrial function during ischemia in the dog. However, oligomycin had only a very small and transient effect on ATP depletion and mitochondrial function in the rat. This was apparently so because of the fivefold higher rate of glycolytic ATP production as well as the nearly threefold higher total nonmitochondrial ATPase activity of ischemic rat compared with ischemic dog heart. These results suggest that although the inhibition of the mitochondrial ATPase makes a major contribution to ATP conservation in ischemic dog heart, it makes only a very small contribution in rat.


2002 ◽  
Vol 75 (5) ◽  
pp. 1951-1961 ◽  
Author(s):  
Mathieu Lesort ◽  
Janusz Tucholski ◽  
Jianwen Zhang ◽  
Gail V. W. Johnson

2008 ◽  
Vol 3 (6) ◽  
pp. 965-976 ◽  
Author(s):  
Andrey V Kuznetsov ◽  
Vladimir Veksler ◽  
Frank N Gellerich ◽  
Valdur Saks ◽  
Raimund Margreiter ◽  
...  

2004 ◽  
Vol 137 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Dzhamilja Safiulina ◽  
Allen Kaasik ◽  
Evelin Seppet ◽  
Nadezhda Peet ◽  
Alexander Zharkovsky ◽  
...  

2017 ◽  
Vol 114 (7) ◽  
pp. 1732-1737 ◽  
Author(s):  
Devin K. Schweppe ◽  
Juan D. Chavez ◽  
Chi Fung Lee ◽  
Arianne Caudal ◽  
Shane E. Kruse ◽  
...  

Mitochondrial protein interactions and complexes facilitate mitochondrial function. These complexes range from simple dimers to the respirasome supercomplex consisting of oxidative phosphorylation complexes I, III, and IV. To improve understanding of mitochondrial function, we used chemical cross-linking mass spectrometry to identify 2,427 cross-linked peptide pairs from 327 mitochondrial proteins in whole, respiring murine mitochondria. In situ interactions were observed in proteins throughout the electron transport chain membrane complexes, ATP synthase, and the mitochondrial contact site and cristae organizing system (MICOS) complex. Cross-linked sites showed excellent agreement with empirical protein structures and delivered complementary constraints for in silico protein docking. These data established direct physical evidence of the assembly of the complex I–III respirasome and enabled prediction of in situ interfacial regions of the complexes. Finally, we established a database and tools to harness the cross-linked interactions we observed as molecular probes, allowing quantification of conformation-dependent protein interfaces and dynamic protein complex assembly.


2017 ◽  
Vol 70 (11-12) ◽  
pp. 445-448
Author(s):  
Enis Garipi ◽  
Aleksandra Rakovac ◽  
Otto Barak ◽  
Damir Lukac ◽  
Nada Naumovic ◽  
...  

Mitochondria are ubiquitous organelles of eukaryotic cells and they are the mayor site of generating energy in the form of adenosine triphoshate through the process of oxidative phosphorylation. Analysis and estimation of mitochondrial function is of outmost importance when it comes to studying intracellular energy metabolism, mechanisms of apoptosis, signaling pathways, calcium storage and the pathophysiology of a large spectrum of human diseases including various neurodegenerative diseases, myopathies, metabolic syndromes and cancer. Respiratory capacity analysis covers one of the many roles that mitochondria play in living cells and it provides us with useful data about functional integrity of mitochondria. Assessment of individual respiratory chain complexes or other mitochondrial enzymes has been widely used to estimate mitochondrial function and dysfunction but it neglects the influence of complex structural and functional interplay of mitochondrial proteins and enzymes and plasmic compounds. Another method that emphasises the importance of studying intact mitochondria is in vitro technique, and although it has many advantages, in some aspects it is far from being representative when it comes to functional assessment of mitochondria. From the perspective of energy production and consumption, the cardiac muscle is a highly demanding tissue and it is the well functioning of mitochondria that is conditio sine qua non for this nature to be fulfilled. In cooperation with the University of Split School of Medicine in Split and under the mentorship of Prof. Marko Ljubkovic, the Department of Physiology of the Faculty of Medicine Novi Sad works on introducing in situ approaches in the analysis of respiratory mitochondrial function in skinned muscle fibers of human cardiac tissue.


2014 ◽  
Vol 46 (14) ◽  
pp. 505-511 ◽  
Author(s):  
Katrine Hordnes Slagsvold ◽  
Anne Berit Johnsen ◽  
Øivind Rognmo ◽  
Morten Andre Høydal ◽  
Ulrik Wisløff ◽  
...  

Atrial fibrillation (AF) is the most common cardiac arrhythmia with a potential to cause serious complications. Mitochondria play central roles in cardiomyocyte function and have been implicated in AF pathophysiology. MicroRNA (miR) are suggested to influence both mitochondrial function and the development of AF. Yet mitochondrial function and miR expression remain largely unexplored in human atrial tissue. This study aims to investigate mitochondrial function and miR expression in the right (RA) and left atria (LA) of patients with AF and sinus rhythm (SR). Myocardial tissue from the RA and LA appendages was investigated in 37 patients with AF ( n = 21) or SR ( n = 16) undergoing coronary artery bypass surgery and/or heart valve surgery. Mitochondrial respiration was measured in situ after tissue permeabilization by saponin. MiR expression was assessed by miR array and real-time quantitative reverse-transcription polymerase chain reaction. Maximal mitochondrial respiratory rate was increased in both RA and LA tissue of patients with AF vs. SR. Biatrial downregulation of miR-208a and upregulation of miR-106b, -144, and -451 were observed in AF vs. SR. In addition, miR-15b was upregulated in AF within RA only, and miR-106a, -18a, -18b, -19a, -19b, -23a, -25, -30a, -363, -486-5p, -590-5p, and -93 were upregulated in AF within LA only. These findings suggest that mitochondrial function and miR are involved in AF pathophysiology and should be areas of focus in the exploration for potential novel therapeutic targets.


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