Author/Editor		Honzak, Lidija
Title		Preučevanje funkcijskih stanj mitohondrijev z EPR oksimetrijo
Translated title		The study of functional states of mitochondria with EPR oximetry
Type		monografija
Place		Ljubljana
Publisher		Univerza v Ljubljani, Medicinska fakulteta
Publication year		1995
Volume		str. 49
Language		slo
Abstract		Mitochondria are the subcellular organelles where ATP is synthesized in the process of oxidative phosphorylation. As the high-energy electrons from NADH and FADH2 are transported down the respiratory chain in the mitochondrial inner membrane, the energy is released and is used to pump protons (H+) from the mitochondrial matrix to the intermembrane space. This creates an electrochemical proton gradient across the inner membrane of the mitochondria Back flow of H+ down this gradient is, in turn, used to drive the membrane-bound enzyme ATP synthase, which catalyses the formation of ATP. The respiration rate of isolated mitochondria is regulated by the ratio ATP/ADP.Pi. It was found that the respiration rate in vivo, is regulated intramuscularly in the same way (Brindle KM et al 1989). In different pathological situations, as well as extreme physiological trauma, hypoxia and even anoxia can occur. In this situation, ATP can be synthesized anaerobically. The end product of anaerobic metabolism is lactic acid, which lowers intramuscular pH. In some pathological situations, like ischemia, the diffusion of C02 which is produced in citric acid cycle in mitochondrial matrix is limited due to vasoconstriction. Higher concentrations of CO2, lower pH of citosol and matrix. The aim of this work was to study the influence of hypoxia and acidose on the oxidative phosphorylation of skeletal muscle mitochondria. Since the polarographic method with the Clark electrode is not sensitive enough for measurements of respiration rates in hypoxia, we developed the EPR-spin probe oximetry. We measured the respiration rate of isolated mitochondria and mitochondria in situ in muscle fibers. We measured the respiration rate of isolated mitochondria in buffers with different pH (7.4-6.2) and found that an acidic pH didn't influence the respiration rate. (Abstract truncated at 2000 characters.)
Descriptors		MITOCHONDRIA, MUSCLE ACIDOSIS ANOXIA HYDROGEN-ION CONCENTRATION ELECTRON SPIN RESONANCE SPECTROSCOPY RATS OXYGEN OXYGEN CONSUMPTION CELL RESPIRATION SPIN LABELS PIPERIDINES