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Titolo:
OXIDATIVE-PHOSPHORYLATION IN MYOCARDIAL MITOCHONDRIA IN-SITU - A CALORIMETRIC STUDY ON PERMEABILIZED CARDIAC-MUSCLE PREPARATIONS
Autore:
KOHNKE D; SCHRAMM M; DAUT J;
Indirizzi:
UNIV MARBURG,INST NORMAL & PATHOL PHYSIOL,DEUTSCHHAUSTR 2 D-35033 MARBURG GERMANY UNIV MARBURG,INST NORMAL & PATHOL PHYSIOL D-35033 MARBURG GERMANY TECH UNIV MUNICH,INST PHYSIOL D-8000 MUNICH GERMANY
Titolo Testata:
Molecular and cellular biochemistry
fascicolo: 1-2, volume: 174, anno: 1997,
pagine: 101 - 113
SICI:
0300-8177(1997)174:1-2<101:OIMMI->2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEART-MITOCHONDRIA; CREATINE-KINASE; RAT-HEART; INTERMEMBRANE SPACE; SPECIES-DIFFERENCES; ENERGY-METABOLISM; FORCE PRODUCTION; ATPASE ACTIVITY; OUTER-MEMBRANE; FREE CALCIUM;
Keywords:
CALORIMETRY; CARDIAC MUSCLE; MITOCHONDRIA; OXIDATIVE PHOSPHORYLATION; ATRACTYLOSIDE; DINITROPHENOL; ECTONUCLEOTIDASE; RESPIRATORY CONTROL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
52
Recensione:
Indirizzi per estratti:
Citazione:
D. Kohnke et al., "OXIDATIVE-PHOSPHORYLATION IN MYOCARDIAL MITOCHONDRIA IN-SITU - A CALORIMETRIC STUDY ON PERMEABILIZED CARDIAC-MUSCLE PREPARATIONS", Molecular and cellular biochemistry, 174(1-2), 1997, pp. 101-113

Abstract

A novel flow calorimetric technique was developed to study the energyturnover of myocardial mitochondria. Cylindrical strands of cardiac muscle (trabeculae) weighing 100-500 mu g were isolated from guinea-pigheart and mounted in a tubular recording chamber which was continuously perfused with physiological salt solution at 37 degrees C. The temperature difference between the upstream and the downstream side of thechamber, which is proportional to the rate of heat production of the trabecula, was measured at high resolution. In this way the rate of energy expenditure of isolated cardiac muscle could be recorded continuously for several hours. When the preparations were superfused with an 'intracellular' solution containing 5 mM pyruvate and 2 mM malate as substrates, permeabilization of the sarcolemma with 25 mu M digitonin induced a marked increase in the measured heat rate in the presence of 2 mM ADP. The major fraction of the ADP sensitive heat production (83%) could be blocked with 400 mu M atractyloside, an inhibitor of the adeninenucleotide translocase, and by 600 mu M alpha-cyano-4-hydroxycinnamate, an inhibitor of monocarboxylate/H+ co-transport. The atractyloside sensitive heat production was abolished in anoxic solution. These results suggest that the atractyloside-sensitive heat production (21.8+/- 3.5 mW cm(-3) of tissue) was attributable to oxidative phosphorylation. The mitochondria apparently remained intact after treatment with digitonin, since application of the uncoupler 2,4-dinitrophenol (DNP) produced a very large increase in heat rate. A minor fraction of theheat rate induced by ADP in permeabilized cardiac muscle preparations(17%) was not sensitive to atractyloside. This component was also seen before application of digitonin and was probably related to ectonucleotidases. In conclusion, our calorimetric technique allows investigation of the energy metabolism of myocardial mitochondria 'in situ', i.e. without destroying the microarchitecture of cardiac muscle cells.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 10:04:22