scholarly journals THE OXYGEN CONSUMPTION OF FROG NERVE DURING STIMULATION

1927 ◽  
Vol 10 (5) ◽  
pp. 767-779 ◽  
Author(s):  
Wallace O. Fenn
Keyword(s):  
Oxygen Consumption ◽  
Sciatic Nerve ◽  
Oxygen Tension ◽  
Heat Production ◽  
Nerve Impulse ◽  
Excess Oxygen ◽  
Causal Connection ◽  
Cent Increase ◽  
Rate Of Oxygen Consumption ◽  
Frequency Of Stimulation

1. The resting rate of oxygen consumption of the excised sciatic nerve of the frog is 1.23 c.mm. of oxygen per gm. of nerve per minute. 2. During stimulation with an induction coil with 100 make and 100 break shocks per second there is an excess oxygen consumption amounting on the average to 0.32 c.mm. of oxygen per gm. of nerve per minute of stimulation, or a 26 per cent increase over the resting rate. 3. The magnitude of the excess oxygen consumption in stimulation, in agreement with the all-or-none law, is not markedly influenced by considerable variations in the intensity of stimulation. 4. Increasing the frequency of stimulation from 100 to 200 shocks per second increases the extra oxygen used only 1.12–1.18 times. The same change in frequency of stimulation increases the negative variation 1.15 times and the heat production about 1.25 times (Hill). 5. This parallelism between the excess oxygen and the negative variation argues definitely for some causal connection between the excess oxygen and the nerve impulse itself. 6. Calculation shows that the oxygen tension inside these nerves was not zero.

Critical oxygen tensions in newborn, young, and adult mice

1963 ◽  
Vol 205 (2) ◽  
pp. 325-330 ◽  
Author(s):  
S. Cassin
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Tension ◽  
Environmental Temperature ◽  
Mild Hypothermia ◽  
Newborn Mouse ◽  
Newborn Mice ◽  
Adult Mice ◽  
Critical Oxygen ◽  
Rate Of Oxygen Consumption ◽  
Oxygen Tensions

Critical oxygen tensions of newborn, young, and adult mice are presented. At neutral environmental temperature, oxygen consumption of newborn mice is unaffected by reducing the oxygen tension of inspired air to 85 mm Hg. Five-day-old mice, at neutral environmental temperature, tolerate a decrease in ambient oxygen tension to 100 mm Hg without a depression of oxygen consumption. Adult mice behave in a qualitatively similar fashion. When the ambient temperature is lowered below neutral, the mice are unable to maintain a constant oxygen consumption if hypoxia is induced. It appears as though the depression of oxygen consumption during hypoxia is linearly related to the hypothermic increment to metabolism: the greater the extra oxygen consumption, the more readily it is reduced. Although the newborn mouse is unable to combat hypothermia effectively, it does respond to mild hypothermia for short periods by increasing its rate of oxygen consumption. Evidence is presented of a rapid maturation of temperature controlling mechanisms during growth.

The Respiratory Physiology of the Marine Nematodes Enoplus Brevis (Bastian) and E. Communis (Bastian)

1973 ◽  
Vol 59 (1) ◽  
pp. 255-266
Author(s):  
H. J. ATKINSON
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Oxygen Tension ◽  
Dry Weight ◽  
Respiratory Physiology ◽  
Rate Of Oxygen Consumption ◽  
Oxygen Tensions ◽  
The Difference ◽  
Relationship Of ◽  
The Relationship

1. The rate of oxygen consumption of individual males of Enoplus brevis and E. communis was measured at 15 °C and at each of four oxygen tensions, 135, 75, 35, and 12 Torr, after at least 12 h experience of these conditions. 2. It was clearly demonstrated that the level of oxygen consumption of both species was reduced by each lowering of the imposed oxygen tension. 3. In all cases the oxygen consumption of each species fell with increasing body size. On a unit dry-weight basis the oxygen consumption of E. brevis is greater than that of the larger E. communis, but after allowing for the difference of body size the two species have more or less similar oxygen uptakes at all oxygen tensions. 4. In E. brevis oxygen tension influenced the relationship of body size and metabolism, the slope relating oxygen consumption and body weight becomes steeper with decreasing oxygen tension. This effect was not shown by E. communis. 5. Some general factors influencing the availability of oxygen to nematodes are considered.

scholarly journals THE RESPIRATION OF LUMINOUS BACTERIA AND THE EFFECT OF OXYGEN TENSION UPON OXYGEN CONSUMPTION

1929 ◽  
Vol 13 (1) ◽  
pp. 27-45 ◽  
Author(s):  
Charles S. Shoup
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Oxygen Tension ◽  
Small Cells ◽  
Pure Oxygen ◽  
Catalytic Surfaces ◽  
Rate Of Oxygen Consumption ◽  
Luminous Bacteria ◽  
Effect Of Oxygen

1. The respiration of luminous bacteria has been studied by colorimetric and manometric methods. 2. Limulus oxyhaemocyanin has been used as a colorimetric indicator of oxygen consumption and indicator dyes were used for colorimetric determination of carbon dioxide production. 3. The Thunberg-Winterstein microrespirometer has been used for the measurement of the rate of oxygen consumption by luminous bacteria at different partial pressures of oxygen. 4. The effect of oxygen concentration upon oxygen consumption has been followed from equilibrium with air to low pressures of oxygen. 5. Luminous bacteria consume oxygen and produce carbon dioxide independent of oxygen pressures from equilibrium with air (152 mm.) to approximately 22.80 mm. oxygen or 0.03 atmosphere. 6. Dimming of a suspension of luminous bacteria occurs when oxygen tension is lowered to approximately 2 mm. Hg (0.0026 atmosphere) and when the rate of respiration becomes diminished one-half. 7. Pure nitrogen stops respiratory activity and pure oxygen irreversibly inhibits oxygen consumption. 8. The curve for rate of oxygen consumption with oxygen concentration is similar to curves for adsorption of gasses at catalytic surfaces, and agrees with the Langmuir equation for the expression of the amount of gas adsorbed in unimolecular layer at catalytic surfaces with gas pressure. 9. A constant and maximum rate of oxygen consumption occurs in small cells when oxygen concentration becomes sufficient to entirely saturate the surface of the oxidative catalyst of the cell.

scholarly journals THE OXYGEN CONSUMPTION OF ESCHERICHIA COLI DURING THE LAG AND LOGARITHMIC PHASES OF GROWTH

1932 ◽  
Vol 15 (6) ◽  
pp. 691-708 ◽  
Author(s):  
Donald S. Martin
Keyword(s):  
Escherichia Coli ◽  
Oxygen Consumption ◽  
Surface Area ◽  
Growth Curve ◽  
Heat Production ◽  
Lag Phase ◽  
Maximum Oxygen Consumption ◽  
Average Cell ◽  
Co2 Output ◽  
Rate Of Oxygen Consumption

The oxygen consumption of rapidly growing cultures of Esch. coli (S) have been measured by means of Fenn's respirometer. The rate of oxygen consumption of a growing culture uniformly attains a phase of logarithmic increase before the growth curve of the organisms becomes logarithmic. The rate of oxygen consumption per cell increases rapidly from the time of inoculation to a point of maximum respiration near the end of the lag phase of the growth curve, followed by a gradual decrease in the respiratory rate. The surface area of the average cell when plotted against time passes through a point of maximum surface area which coincides with the point of maximum oxygen consumption per cell. Figures obtained by different methods, CO2 output and heat production when reduced to the same units, agree remarkably well.

Oxygen consumption in the avascular guinea pig retina

1996 ◽  
Vol 271 (3) ◽  
pp. H1162-H1165 ◽  
Author(s):  
S. Cringle ◽  
D. Y. Yu ◽  
V. Alder ◽  
E. N. Su ◽  
P. Yu
Keyword(s):  
Oxygen Consumption ◽  
Guinea Pig ◽  
Oxygen Tension ◽  
Physiological State ◽  
High Oxygen ◽  
Excess Oxygen ◽  
Low Oxygen ◽  
Inner Retina ◽  
Oxygen Sensitive

Oxygen consumption across the retina of a mammal with a naturally avascular retina has not previously been investigated. The oxygen consumption across the avascular retina of the guinea pig was measured in vivo by spatial analysis of the intraretinal oxygen profile. The avascular nature of the guinea pig retina allows the inner retina to be included in the analysis without disrupting the normal physiological state of the retina. Oxygen-sensitive microelectrodes (1-micron tip) were used to make high-resolution measurements of oxygen tension through the retina of anesthetized, mechanically ventilated guinea pigs (n = 10). Oxygen profiles were then analyzed in terms of oxygen tension as a function of distance from the choriocapillaris/Bruch's membrane, and the data were fitted to an established mathematical model of retinal oxygen consumption. The average oxygen consumption of the full thickness of the guinea pig retina was 1.1 +/- 0.09 ml O2.min-1 x 100 g-1 (n = 10). The average oxygen consumption of the outer half of the retina was 2.07 +/- 0.17 ml O2.min-1 x 100 g-1, while that of the inner half was only 0.12 +/- 0.04 ml O2.min-1 x 100 g-1. A localized region of high oxygen consumption was identified in the outer retina in every case, and this region accounted for an average of 93.9 +/- 2.0% of the total retinal oxygen consumption. Only 5.2 +/- 1.4% of the total oxygen consumption was attributable to the inner half of the retina. When choroidal oxygen tension was increased via a combination of systemic hyperoxia and hypercapnia, high oxygen levels could be sustained in all retinal layers. Under these conditions of an excess oxygen supply, the inner retina still consumed only 0.45 +/- 0.11 ml O2.min-1 x 100 g-1, which was 13.8 +/- 2.5% of the total retinal oxygen consumed. The relatively low oxygen consumption in the inner retina of the guinea pig may reflect an interesting adaptation to the constraints imposed by the absence of a retinal circulation in this species.

The magnitude of noradrenaline-induced thermogenesis in the bat (Myotis lucifugus) and its relation to arousal from hibernation

1968 ◽  
Vol 46 (5) ◽  
pp. 713-718 ◽  
Author(s):  
J. S. Hayward
Keyword(s):  
Oxygen Consumption ◽  
Heat Production ◽  
High Capacity ◽  
Fold Increase ◽  
Myotis Lucifugus ◽  
Maximal Rate ◽  
Significant Difference ◽  
Rate Of Oxygen Consumption ◽  
Very High

The effect of subcutaneously injected noradrenaline upon the rate of oxygen consumption of bats (Myotis lucifugus) has been evaluated. Maximal responses were obtained with doses between 2 and 15 mg noradrenaline/kg. These doses increased the oxygen consumption to a mean of 7.93 ml O2/g per h from a pretreatment mean of 0.75 ml O2/g per h, representing a 10.6-fold increase. A survey of the literature shows that the magnitude of this response exceeds by several times the magnitude of response observed for any other species. There was no significant difference between the responses of nonhibernated and hibernated bats. The maximal rate of thermogenesis during arousal from hibernation was a mean of 10.57 ml O2/g per h. In comparison with this value, the maximum noradrenaline-induced thermogenesis of hibernated bats was 8.62 ml O2/g per h. This provides an estimate (81.6%) of the involvement of noradrenaline-induced thermogenesis in the process of arousal from hibernation. These findings corroborate previously reported evidence that hibernating bats exhibit a very high capacity for nonshivering heat production.

Shivering and nonshivering thermogenic responses of cold-exposed rats to hypothalamic warming

1975 ◽  
Vol 228 (5) ◽  
pp. 1519-1524 ◽  
Author(s):  
CA Fuller ◽  
BA Horwitz ◽  
JM Horowitz
Keyword(s):  
Oxygen Consumption ◽  
Heat Production ◽  
Neural Control ◽  
Nonshivering Thermogenesis ◽  
Neural Controllers ◽  
Rate Of Oxygen Consumption ◽  
Exposed Animal ◽  
Unanesthetized Animals ◽  
Shivering Thermogenesis ◽  
Rule Out

The concurrent neural control of two thermoregulatory responses, shivering thermogenesis (ST) and nonshivering thermogenesis (NST), was investigated in chronically implanted cold-exposed rats. The effects of heating the preoptic/anterior hypothalamus (POAH) on shivering and on the rate of oxygen consumption (Vo2) were measured in these unanesthetized animals. With ambient temperature maintained constant (at some value between 10 and 16 degrees C), warming the hypothalamus 2-3 degrees C resulted in a significant decrease in Vo2 (Psmaller than 0.001) and an increase in shivering (Psmaller than .01), these responses being reversed on cessation of hypothalamic warming. These results are consistent with the proposal that, in the cold-exposed animal, elevated POAH temperatures directly inhibit NST even though shivering may increase (possibly as a compensation for the decrease in nonshivering heat production). They also rule out the possibility that, in the rat, signals from cutaneous and hypothalamic thermoreceptors are integrated in an indentical manner by the neural controllers for ST and NST.

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