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Titolo:
PHOSPHOCREATINE HYDROLYSIS DURING SUBMAXIMAL EXERCISE - THE EFFECT OFFIO2
Autore:
HASELER LJ; RICHARDSON RS; VIDEEN JS; HOGAN MC;
Indirizzi:
UNIV CALIF SAN DIEGO,DEPT MED 0623A,DIV PHYSIOL LA JOLLA CA 92093
Titolo Testata:
Journal of applied physiology (1985)
fascicolo: 4, volume: 85, anno: 1998,
pagine: 1457 - 1463
SICI:
8750-7587(1998)85:4<1457:PHDSE->2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
CELLULAR-ENERGY METABOLISM; PULMONARY OXYGEN-UPTAKE; HUMAN SKELETAL-MUSCLE; TISSUE RESPIRATION; MODERATE EXERCISE; CREATINE-KINASE; DOG MUSCLE; KINETICS; O-2; ENERGETICS;
Keywords:
FRACTION OF INSPIRED OXYGEN; SKELETAL MUSCLE; INTRACELLULAR OXYGENATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
39
Recensione:
Indirizzi per estratti:
Citazione:
L.J. Haseler et al., "PHOSPHOCREATINE HYDROLYSIS DURING SUBMAXIMAL EXERCISE - THE EFFECT OFFIO2", Journal of applied physiology (1985), 85(4), 1998, pp. 1457-1463

Abstract

There is evidence that the concentration of the high-energy phosphatemetabolites may be altered during steady-state submaximal exercise bythe breathing of different fractions of inspired O-2 (FIO2). Whereas it has been suggested that these changes may be the result of differences in time taken to achieve steady-state O-2 uptake (Vo(2)) at different FIO2 values, we postulated that they are due to a direct effect ofO-2 tension. We used P-31-magnetic resonance spectroscopy during constant-load, steady-state submaximal exercise to determine 1) whether changes in high-energy phosphates do occur at the same Vo(2) with variedFIO2 and 2) that these changes are not due to differences in Vo(2) onset kinetics. Six male subjects performed steady-state submaximal plantar flexion exercise [7.2 +/- 0.6 (SE) W] for 10 min while lying supine in a 1.5-T clinical scanner. Magnetic resonance spectroscopy data were collected continuously for 2 min before exercise, 10 min during exercise, and 6 min during recovery. Subjects performed three different exercise bouts at constant load with the FIO2 switched after 5 min of the 10-min exercise bout. The three exercise treatments were 1) FIO2 of0.1 switched to 0.21, 2) FIO2 of 0.1 switched to 1.00, and 3) FIO2 of1.00 switched to 0.1. For all three treatments, the Fro, switch significantly (P less than or equal to 0.05) altered phosphocreatine: 1) 55.5 +/- 4.8 to 67.8 +/- 4.9% (%rest); 2) 59.0 +/- 4.3 to 72.3 +/- 5.1%;and 3) 72.6 +/- 3.1 to 64.2 +/- 3.4%, respectively. There were no significant differences in intracellular pH for the three treatments. Theresults demonstrate that the differences in phosphocreatine concentration with varied FIO2 are not the result of different Vo(2) onset kinetics, as this was eliminated by the experimental design. These data also demonstrate that changes in intracellular oxygenation, at the same work intensity, result in significant changes in cell homeostasis and thereby suggest a role for metabolic control by O-2 even during submaximal exercise.

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Documento generato il 06/04/20 alle ore 01:47:40