Effect of cold acclimation on norepinephrine stimulated oxygen consumption in muscle

Summary The purpose of this study was to determine the effect of norepinephrine (NE) on oxygen consumption ( ) of perfused (constant flow) muscle in cold acclimated (CA) and control rats. Infusion of NE for a five minute period caused an increase in of similar magnitude in both groups. Infusion of NE for 30 min resulted in an elevated steady state in the cold acclimated group, while the control group showed only an initial increase in followed by a continual decline during the remainder of the 30 min infusion period. These results suggest that when rats are challenged by cold exposure, the magnitude of the initial muscle response to NE by control and acclimated rats is the same, but a useful sustained higher muscle oxygen consumption is found only in the cold acclimated animals.Abbreviations CA cold acclimated - NE norepinephrine     

Effects of electrical muscle stimulation on oxygen consumption

Electrical muscle stimulation (EMS) devices are being marketed as weight/ fat loss devices throughout the world. Commercially available stimulators have the ability to evoke muscle contractions that may affect caloric expenditure while the device is being used. The aim of this study was to test the effects of two different EMS devices (Abtronic and Feminique) on oxygen consumption at rest. Subjects arrived for testing after an overnight fast, had the devices fitted, and then positioned supine with expired air measured to determine oxygen consumption. After a 10-minute acclimation period, oxygen consumption was measured for 20 minutes with the device switched off (resting) then 20 minutes with the device switched on (stimulated). There were no significant differences (p > 0.05) in oxygen consumption between the resting and stimulated periods with either the Abtronic (mean +/- SD; resting, 3.40 +/- 0.44; stimulated, 3.45 +/- 0.53 ml of O(2).kg(-1).min(-1)) or the Feminique (resting, 3.73 +/- 0.45; stimulated, 3.75 +/- 0.46 ml of O(2).kg(-1).min(-1)). In summary, the EMS devices tested had no effect on oxygen consumption during muscle stimulation.     

Effect of rocker shoe radius on oxygen consumption rate in young able-bodied persons

We studied oxygen consumption rate of eleven young able-bodied persons walking at self-selected speed with five different pairs of shoes: one regular pair without rocker soles (REG) and four pairs with uniform hardness (35-40 shore A durometer) rocker soles of different radii (25% of leg length (LL) (R25), 40% LL (R40), 55% LL (R55), and infinite radius (FLAT)). Rocker soled shoes in the study were developed to provide similar vertical lift (three inches higher than the REG shoes condition). Oxygen consumption rate was significantly affected by the use of the different shoes (p<0.001) and pairwise comparisons indicated that persons consumed significantly less oxygen (per minute per kilogram of body mass) when walking on the R40 shoes when compared with both the FLAT (p<0.001) and REG (p=0.021) shoe conditions. Oxygen consumption was also significantly less for the R25 shoes compared with the FLAT shoes (p=0.005) and for the R55 shoes compared with FLAT shoes (p=0.027). The three-inch lift on the FLAT shoe did not cause a significant change in oxygen consumption compared to the shoe without the lift (REG).     

Effect of various respiration substrates and growth marker proteins on oxygen consumption in rabbit heart mitochondria

Oxygen uptake by myocardium mitochondria of healthy, carcinomatous and new-born rabbits in the presence of different substrates was studied under the effect of immunoglobulin G and beta-globulin peculiar to the normal and malignant growth. It is stated that the growth marker proteins representing a subfraction of immunoglobulin G of tumour patients blood serum and beta-globulin of new-born rabbits blood serum in the presence of pyruvate, alpha-ketoglutarate and glutamate inhibit the oxygen uptake by healthy rabbits heart mitochondria. Studies conducted on mitochondria of new-born and carcinomatous rabbits show that the action of the proteins under study depends on the respiration substrate. In the presence of succinate the proteins under study activate the oxygen uptake and pyruvate, alpha-ketoglutarate and glutamate inhibit this process. A conclusion is drawn that the effect of proteins peculiar to the growth process on the biological oxidation depends both on the substrate and structural state of mitochondria.     

Biphasic oxygen kinetics of cellular respiration and linear oxygen dependence of antimycin A inhibited oxygen consumption

Oxygen kinetics in fibroblasts was biphasic. This was quantitatively explained by a major mitochondrial hyperbolic component in the low-oxygen range and a linear increase of rotenone-and antimycin A-inhibited oxygen consumption in the high-oxygen range. This suggests an increased production of reactive oxygen species and oxidative stress at elevated, air-level oxygen concentrations. The high oxygen affinity of mitochondrial respiration provides the basis for the maintenance of a high aerobic scope at physiological low-oxygen levels, whereas further pronounced depression of oxygen pressure induces energetic stress under hypoxia.     

Effect of trifluoperazine on skeletal muscle mitochondrial respiration

The effect of trifluoperazine on the respiration of porcine liver and skeletal muscle mitochondria was investigated by polarographic and spectroscopic techniques. Low concentrations of trifluoperazine (88 nmol/mg protein) inhibited both the ADP- and Ca²⁺-stimulated oxidation of succinate, and reduced the values of the respiratory control index and the $\text{ADP}\text{O}$ and $\text{Ca}{}^{\mathrm{2+}}\text{O}$ ratio. High concentrations inhibited both succinate and ascorbate plus tetramethyl-p-phenylenediame (TMPD) oxidations, and uncoupler (carbonyl cyanide p-trifluromethoxyphenylhydrazone) and Ca²⁺-stimulated respiration. Porcine liver mitochondria were more sensitive to trifluoperazine than skeletal muscle mitochondria. Trifluoperazine inhibited the electron transport of succinate oxidation of skeletal muscle mitochondria within the cytochrome b-c₁ and cytochrome c₁-aa₃ segments of the respiratory chain system. 233 nmol trifluoperazine/mg protein inhibited the aerobic steady-state reduction of cytochrome c₁ by 92% with succinate as substrate, and of cytochrome c and cytochrome aa₃ by 50–60% with ascorbate plus TMPD as electron donors. Trifluoperazine can thus inhibit calmodulin-independent reactions particularly when used at high concentrations.     

日本三角涡虫的耗氧率和窒息点

应用静水呼吸室法,测定10℃、14℃、18℃、22℃、26℃和32℃温度下日本三角涡虫（Dugesiaj aponica）的耗氧率和窒息点,并测定涡虫耗氧率是否与温度和昼夜节律有关。结果表明,10℃和14℃涡虫耗氧率很低;18℃、26℃和32℃耗氧率较高;22℃涡虫耗氧率低于18℃、26℃和32℃条件下的耗氧率（P〈0,05）高于10℃和14℃条件下的耗氧率（P〈0．05）。18℃时窒息点最高,22℃窒息点最低。10℃、14℃、18℃、22℃、26℃和32℃温度下涡虫的窒息时间分别为125h,120h,55h,42h,37．5h和18．5h。18℃、22℃和26℃3个温度下涡虫耗氧率都呈昼夜节律性变化,白天耗氧率低,晚上耗氧率高（P〉0．05）。同一时间段比较,22℃耗氧率也最低。     

Monitoring the rate of oxygen consumption in plant cell suspensions

A method is described that allows the rate of oxygen consumption to be monitored in plant cell suspensions. The method utilized oxygen electrodes placed in beakers of plant cells subjected to various treatments. The voltage readings from calibrated electrodes were converted to % oxygen (100% equals air equilibration) and the rate of oxygen consumption was estimated by calibration graphs made with no cells present. This system simultaneously monitors one to sixteen or more samples, allowing comparison of treatments on identically treated cells. We have used this method to study the respiratory burst of plant cells produced in response to viable or heat-killed bacteria. Because the system was computer-monitored and open to the atmosphere, data could be collected over several hours. Various factors that affected the measurement of dissolved oxygen concentration with this technique were explored and considered. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of exogenous lactate on pulsation rate and oxygen consumption of the isolated heart of thermally acclimated goldfish

1. 1.Pulsation rate as well as oxygen consumption of 10°C-acclimated golfish heart was higher in the lactate medium than in the glucose medium, but such differences was indistinct in 25°C-acclimated fish.

2. 2.Lactate and glycogen content and its consumption of the isolated heart dependent on the acclimation temperature.

3. 3.These results suggest that temperature acclimation induces change in availability of the substrates to the heart.

Steady-state measurements of respiration rate with an oxygen electrode.

An oxygen electrode was developed which measures steady-state respiration rates in a volume of 0.25 ml and at oxygen concentrations as low as 0.1 μm. The steady state was achieved by pumping air-equilibrated buffer into the respirometer at various rates. The method is most suitable for tissue slices.     

Oxygen mass transfer and oxygen respiration rate measurements utilizing fast response oxygen electrodes

Oxygen transfer coefficient and oxygen respiration rate measurements in stirred tank reactors or fermentors have been carried out utilizing currently available dissolved oxygen electrodes. Techniques based on previously derived theory¹ have been put to experimental tests and found to adequately describe the oxygen transfer phenomena observed in air–water systems and a fermenting broth.     

Estimating the rate of oxygen consumption during submersion from the heart rate of diving animals

How animals manage their oxygen stores during diving and other breath-hold activities has been a topic of debate among physiologists for decades. Specifically, while the behavior of free-ranging diving animals suggests that metabolism during submersion must be primarily aerobic in nature, no studies have been able to determine their rate of oxygen consumption during submersion (Vo(2)d) and hence prove that this is the case. In the present study, we combine two previously used techniques and develop a new model to estimate Vo(2)d accurately and plausibly in a free-ranging animal and apply it to data for macaroni penguins (Eudyptes chrysolophus) as an example. For macaroni penguins at least, Vo(2)d can be predicted by measuring heart rate during the dive cycle and the subsequent surface interval duration. Including maximum depth of the dive improves the accuracy of these predictions. This suggests that energetically demanding locomotion events within the dive combine with the differing buoyancy and locomotion costs associated with traveling to depth to influence its cost in terms of oxygen use. This will in turn effect the duration of the dive and the duration of the subsequent recovery period. In the present study, Vo(2)d ranged from 4 to 28 ml.min(-1).kg(-1), indicating that, at least as far as aerobic metabolism was concerned, macaroni penguins were often hypometabolic, with rates of oxygen consumption usually below that for this species resting in water (25.6 ml.min(-1).kg(-1)) and occasionally lower than that while resting in air (10.3 ml.min(-1).kg(-1)).     

Effect of feeding on the respiration rate of the rotifer Brachionus plicatilis

The effect of feeding on the respiration rate of Brachionus plicatilis was studied. Oxygen consumption was determined under two feeding regimes, duplicate feeding and constant feeding. Oxygen consumption rate increased during feeding. The oxygen consumption profile is discussed in relation to the following processes:

1. filtration, mastication, and locomotion during feeding
2. specific dynamic action (SDA)
3. egg formation and routine metabolism.