Improved fatigue resistance not associated with maximum oxygen consumption in creatine-depleted rats

1997 ◽  
Vol 82 (6) ◽  
pp. 1911-1917 ◽  
Author(s):  
T. Tanaka ◽  
Y. Ohira ◽  
M. Danda ◽  
H. Hatta ◽  
I. Nishi
Keyword(s):  
Oxygen Consumption ◽  
Fatigue Resistance ◽  
Oxygen Transport ◽  
High Energy ◽  
Endurance Capacity ◽  
High Energy Phosphates ◽  
Transport Capacity ◽  
Maximum Oxygen Consumption ◽  
Oxygen Transport Capacity ◽  
Hindlimb Muscles

Tanaka, T., Y. Ohira, M. Danda, H. Hatta, and I. Nishi.Improved fatigue resistance not associated with maximum oxygen consumption in creatine-depleted rats. J. Appl. Physiol. 82 (6): 1911–1917, 1997.—Effects of feeding of either creatine or its analog β-guanidinopropionic acid (β-GPA) on endurance work capacity and oxygen consumption were studied in rats. Resting high-energy phosphate contents in hindlimb muscles were lower in the β-GPA group and higher in the creatine group than in controls. The glycogen contents in resting hindlimb muscles of rats fed β-GPA were significantly higher than those in controls. The endurance run and swimming times to exhaustion were significantly greater (32–70%) in the β-GPA group than in the control and creatine groups. However, there were no beneficial effects on the maximum oxygen consumption (V˙o 2 max) and oxygen transport capacity of blood by the feeding of β-GPA. None of these parameters were significantly influenced by creatine supply. Both maximum exercise time andV˙o 2 max in the β-GPA group were not changed by normalization of glycogen levels. The activities of mitochondrial enzymes in skeletal muscles were higher in the β-GPA group than in the controls. Thus endurance capacity is improved if the respiratory capacity of muscles is increased, even when the contents of high-energy phosphates in muscles are lower. Increased endurance capacity was not directly associated with the elevated levels of muscle glycogen, oxygen transport capacity of blood, orV˙o 2 max.

Transient changes in muscle high-energy phosphates during moderate exercise

1993 ◽  
Vol 75 (2) ◽  
pp. 648-656 ◽  
Author(s):  
G. D. Marsh ◽  
D. H. Paterson ◽  
J. J. Potwarka ◽  
R. T. Thompson
Keyword(s):  
Oxygen Consumption ◽  
Steady State ◽  
Recovery Period ◽  
High Energy ◽  
Second Order ◽  
Moderate Intensity ◽  
High Energy Phosphates ◽  
Order Model ◽  
Time Constants ◽  
First Order

The purpose of this study was to use 31P-nuclear magnetic resonance spectroscopy to examine changes in wrist flexor muscle metabolism during the transitions from rest to steady-state exercise (on-transient) and back to rest (off-transient). Five healthy young males (mean age 25 +/- 2 yr) performed a series of square-wave exercise tests, each consisting of 5 min of moderate-intensity work followed by a 5-min recovery period. The subjects repeated this protocol six times, and each individual's results were pooled before analysis. ATP and intracellular pH did not change significantly during exercise or recovery. Phosphocreatine (PCr) declined progressively at the onset of exercise, reaching a plateau after approximately 2 min. A reciprocal increase in Pi occurred during the onset of exercise. During the recovery period PCr was resynthesized, whereas Pi returned to resting levels. The data were plotted as a function of time and fit with both first- and second-order exponential growth or decay models; however, the second-order model did not significantly improve the fit of the data. Time constants for the first-order model of the on- and off-transient responses for both PCr and Pi were approximately 30 s. These values are nearly identical to the time constants for oxygen consumption during submaximal exercise that have been reported previously by several authors. The results of this study show that the metabolism of muscle PCr during steady-state exercise and recovery can be accurately described by a monoexponential model and, further, suggest that a first-order proportionality exists between metabolic substrate utilization and oxygen consumption.

scholarly journals 41. Oxygen transport capacity in the neonatal period

1971 ◽  
Vol 5 (2) ◽  
pp. 91-92
Author(s):  
A Koivikko ◽  
E Länsimies ◽  
J Klossner
Keyword(s):  
Oxygen Transport ◽  
Neonatal Period ◽  
Transport Capacity ◽  
Oxygen Transport Capacity

scholarly journals Mathematical Modeling of Oxygen Transport in Retinal Layers

2019 ◽  
Vol 6 (6) ◽  
pp. 1-4
Author(s):  
Aadesh Kumar ◽  
◽  
Dr. Ram avtar ◽  
Dr. Deepti Seth ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Differential Equation ◽  
Mathematical Model ◽  
Oxygen Consumption ◽  
Oxygen Transport ◽  
Oxygen Supply ◽  
Retinal Vasculature ◽  
Retinal Layer ◽  
Maximum Oxygen Consumption ◽  
Retinal Layers

The retina contains maximum oxygen ( consumption making it particular valuneric to vascular in fults, diminishing oxygen and circulation of nutrients. The goel of this paper to develop a mathematical model for quantitative analysis of transportation of oxygen and consumption in each retinal layer. Such models allows us to predict the effect of qualitatative change in retinal vasculature on oxygen supply in retinal layers. A differential equation , which used in this paper describing how the oxygen transport and cosumpt by the retinal layers.

Adrenergic influences on cardiac function during ventricular fibrillation in isolated rat hearts

1991 ◽  
Vol 261 (5) ◽  
pp. H1452-H1456
Author(s):  
I. Derad ◽  
I. Funk ◽  
P. Pauschinger ◽  
J. Born
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Ventricular Fibrillation ◽  
Cardiac Function ◽  
Coronary Blood Flow ◽  
High Energy ◽  
High Energy Phosphates ◽  
Tissue Concentrations ◽  
Rat Hearts ◽  
Isolated Rat

Effects of norepinephrine (NE, 10(-6) M), epinephrine (E, 10(-6) M), and vehicle on coronary blood flow (CF), oxygen consumption, and lactate release were compared in 32 isolated rat hearts during 5 min of ventricular fibrillation (VF). After VF, tissue concentrations of ATP, AMP, creatinine phosphate (CP), and lactate were measured. Perfusion of treatments started 30 s after onset of VF and was maintained throughout VF. CF during VF was greater (P less than 0.005) during perfusion of E (mean +/- SE, 5.73 +/- 0.15 ml/min) than NE (5.06 +/- 0.32 ml/min) or vehicle (5.11 +/- 0.18 ml/min). Oxygen consumption during VF was higher during perfusion of E (29.5 +/- 0.9 microliters.min(-1).g wet heart wt(-1)) than vehicle (27.3 +/- 0.7 microliters.min(-1).g(-1); P less than 0.05); average oxygen consumption during NE (27.6 +/- 1.4 microliters.min(-1).g(-1)) and vehicle were comparable. After NE, but not E, tissue AMP concentrations were significantly increased, and CP concentrations were reduced compared with vehicle (P less than 0.05). Enhanced consumption of high-energy phosphates during NE suggests that there is also an enhanced demand for oxygen. However, unlike during E, during NE this demand is not met by an augmented CF. Thus, compared with E, NE treatment during VF may increase the risk of hypoxic damage.

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