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  • 2000-2004
  • 1975-1979  (3)
  • 1935-1939
  • 1979  (1)
  • 1976  (2)
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Years
  • 2000-2004
  • 1975-1979  (3)
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 26 (1976), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Synaptosomes incubated in a physiological saline extrude sodium and take up potassium. As would be expected this process is completely blocked by metabolic inhibitors such as cyanide and iodoacetate. However, when metabolic inhibitors are replaced by ouabain (100 μM) there is an increase in the steady state intrasynaptosomal sodium and chloride content even though there is no change in the potassium content. The increases are prevented when synaptosomes are incubated with metabolic inhibitors in addition to ouabain. There is therefore a ouabain-insensitive process that transports sodium, chloride and concomitantly water into synaptosomes. It appears not to function when the supply of metabolic energy is inhibited. The diuretic furosemide (1 mM) in the presence of ouabain inhibits the entry of sodium and chloride without affecting the intrasynaptosomal potassium concentration. Ethacrynic acid (1 mM) has a somewhat similar effect but in addition appears to damage the synaptosome membrane.Kinetic measurements were made of the uptake of sodium, potassium and chloride under conditions of metabolic inhibition and the permeability constants of the membrane determined. Values of 0.068, 0.117 and 0.032 × 10-6 (cm s-1) were found for the permeability constants of the membrane to (respectively) sodium, potassium and chloride. Measurements of the rate of uptake in the presence of ouabain revealed an inwardly directed sodium and chloride flux of 5-20 pmol cm-2 s-1. Calculation of the fluxes from the steady state ion concentrations also reveals an inwardly directed sodium and chloride flux, though of lesser magnitude. The influx of water is less than would be expected to preserve osmotic equality suggesting that the translocation of sodium and chloride is the primary event. Although its function remains uncertain the flux has a considerable effect on the ion content of synaptosomes.
    Type of Medium: Electronic Resource
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  • 2
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    Beverly Hills, Calif. : Periodicals Archive Online (PAO)
    Law and society review. 10:4 (1976:Summer) 547 
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 380 (1979), S. 205-210 
    ISSN: 1432-2013
    Keywords: Lactate ; Muscle fibers ; Recovery exercise ; Bicycle ergometer ; Women
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract After exercise the lactate (La) removal from blood occurs significantly faster during moderate exercise than at rest. However, under both conditions there are considerable inter-individual differences in La removal. These differences in man may depend on the slow-twitch (ST) fiber content of muscle (X1), the La concentration in blood (X2), and the intensity of the recovery exercise (X3). Therefore, multiple regression models were obtained to describe La removal rates with these variables. In 10 women La concentrations were increased via a 6 min bicycle ergometer ride (87%VO2 max) and blood La concentrations were measured every 5 min during 20 min resting and active recovery periods (29–49%VO2 max). For resting recovery only the initial La concentration after the 6 min exercise provided a significant description for La removal in 8 subjects (P=0.03). However, for the active recovery a highly significant description for La removal was obtained: La removal rate (mM/l · min)=0.773×10−2X1+0.321×10−1X2−0.120×10−1X3+0.202 (R=0.91;P=0.01). The statistical independence (P〉0.10) of each of these variables in the model suggests that each is contributing uniquely to the total removal rate of La observed during an active recovery period. The relationship between La removal and %ST fibers may be related to the metabolic and anatomical features of these fibers, the La concentration probably reflects the significance of the mass action effect of La, and the intensity of exercise reflects the role of the muscle's metabolic rate. The present results illustrate that the removal of blood lactate is influenced by the interactive effects of the intensity of the recovery exercise, blood lactate concentration and the ST fiber content of muscle.
    Type of Medium: Electronic Resource
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