Blood oxygen requirements in resting crab (Carcinus maenas) 24 h after feeding

1999 ◽  
Vol 77 (5) ◽  
pp. 784-794 ◽  
Author(s):  
Alexia Legeay ◽  
Jean-Charles Massabuau
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Flow Rate ◽  
Consumption Rate ◽  
Carcinus Maenas ◽  
Blood Flow Rate ◽  
Blood Oxygen ◽  
Partial Pressure Of Oxygen ◽  
Blood Ph ◽  
Oxygen Requirements

Numerous resting unfed water-breathers have a strategy of gas-exchange regulation that consists of setting the arterial partial pressure of oxygen (Pao2) at 1-3 kPa. This raises a question concerning the extent to which physiological functions are limited in this situation. To obtain insight into this problem, we studied the steady-state adaptation of the blood-oxygen transfer system in the crab Carcinus maenas during the doubling of the oxygen consumption rate, Mo2 (i.e., during the period of specific dynamic action of food (SDA)), that occurs 24 h after feeding. We showed that this increase in the oxygen consumption rate 24 h after a meal is not limited by a blood partial pressure of oxygen (Po2) as low as 0.8-1.5 kPa in either normoxia or hypoxia (Po2 of the inspired water = 4 kPa). In normoxia, adaptation of the oxygen-transport system, if any, consisted of a combined set of adaptations of small amplitude (in absolute value), rather than major changes in blood oxygenation status, blood flow rate, or oxygen affinity (although blood pH decreases). In hypoxia, the SDA was mainly associated with an increase in blood flow rate and blood pH, with no changes in blood lactate, urate, calcium, and haemocyanin concentrations. The results are discussed, in an environmental context, in terms of minimal oxygen requirements in water-breathers.

Effect of hemorrhagic hypotension on oxygen consumption of dogs

1964 ◽  
Vol 207 (3) ◽  
pp. 647-649 ◽  
Author(s):  
Elvin E. Smith ◽  
Jack W. Crowell
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Arterial Pressure ◽  
Flow Rate ◽  
Blood Oxygen ◽  
Oxygen Utilization ◽  
Epinephrine Administration ◽  
Utilization Coefficient ◽  
Subsequent Rise

The effects of hematocrit, Dibenzyline, and epinephrine on oxygen consumption were studied in 220 dogs whose arterial pressure was lowered to and maintained at 30 mm Hg. Oxygen consumption was recorded previous to and during the period of hypotension. The average oxygen consumption was 7.20 ml/kg min prior to hemorrhage. Ten minutes after hemorrhage the oxygen consumption was 3.58 ml/kg min (50% of control). After 30 min of hypotension the oxygen consumption was 4.70 ml/kg min (65% of control), and the oxygen consumption increased to 5.33 ml/kg min (74% of control) after 1 hr. Pretreatment with Dibenzyline increased the oxygen consumption during the early stages of hypotension but had little effect in the latter stages. Epinephrine administration decreased the oxygen consumption during the entire hypotensive period. Previous studies have shown that the oxygen utilization coefficient approaches its maximal value during the hypotensive period; therefore, oxygen uptake becomes limited by the blood flow and the changes in oxygen consumption indicate changes in flow rate to active tissue. Simultaneous studies showed that the hematocrit influenced oxygen transport by effects on both the blood oxygen content and the blood flow. The results illustrate that animals with hematocrits of 35–39 are able to transport more oxygen than animals with other hematocrits. Evidence is presented to show that the initial fall and the subsequent rise in oxygen consumption during hypotension may be a local autoregulation of blood flow.

Blood flow and oxygen consumption in avian skeletal muscle during hypoxia

1981 ◽  
Vol 50 (2) ◽  
pp. 450-455 ◽  
Author(s):  
B. R. Grubb
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Flow Rate ◽  
Blood Flow Rate ◽  
Oxygen Extraction ◽  
Arterial Oxygen ◽  
Low Oxygen ◽  
Arterial Oxygen Content ◽  
Hindlimb Muscle

Birds are known to be much more tolerant than mammals to high altitude [low oxygen pressure (PO2)], and it is therefore of interest to know the responses of their muscles to low oxygen. We studied the influence of hypoxia on the rate of blood flow, oxygen extraction, and oxygen consumption (VO2) in resting hindlimb muscle of ducks. We found that during normoxia the VO2 in this muscle mass was similar to resting mammalian red muscle. However, blood flow rate (45 ml x 100 g-1 x min-1) and venous PO2 (70 Torr) were much higher than in resting red or white mammalian muscle. Hypoxia down to 35-40 Torr resulted in no change in blood flow, but oxygen extraction increased dramatically as arterial PO2 fell below 70 Torr. The resting VO2 was maintained even at the lowest arterial oxygen content (5 ml/100 ml). From these experiments it appears as though duck skeletal muscle has a "luxuriant" resting blood flow rate that is sufficient to supply skeletal muscle with adequate oxygen.

Role of splanchnic and lumbar sympathetic nerves in physiologic responses to fever and hypoxia in dogs

1959 ◽  
Vol 196 (3) ◽  
pp. 685-690
Author(s):  
W. G. Kubicek ◽  
W. F. Geber ◽  
J. W. Geiger ◽  
E. A. Johnson
Keyword(s):  
Blood Pressure ◽  
Oxygen Consumption ◽  
Lactic Acid ◽  
Blood Glucose ◽  
Pulse Rate ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Sympathetic Nerves ◽  
Blood Oxygen ◽  
Blood Ph

Induced fever up to 42°C rectal temperature produced an increase in oxygen consumption rate, plasma creatinine, blood lactic acid, hematocrit, blood oxygen content, blood pH, pulse rate, a decrease in blood sugar and a fall in blood CO2 content. Hypoxia superimposed upon the fever tended to produce an increase in blood pressure, hematocrit and pulse rate. Hypoxia probably depressed cerebral cortical activity in the unanesthetized febrile dogs. The most important function of the splanchnic and lumbar sympathetic nerves was apparently the control of the circulatory system and secondly the partial regulation of blood glucose probably through liberation of epinephrine from the adrenal medulla. A reduction in heat tolerance of the animals was observed after sympathectomy. The effects of anesthesia were apparently a reduced sensitivity of the respiratory centers and chemoreceptors. When compared to the unanesthetized experience, lower values were observed for oxygen consumption rate, blood pH, blood oxygen content, hematocrit, plasma creatinine and blood lactic acid, and in higher values for pulse rate, blood pressure, blood CO2 content and blood glucose.

Oxygen Consumption of Embryos and Parents, and Oxygen Transfer Characteristics Within the Ovary of Two Species of Viviparous Seaperch, Rhacochilus vacca and Embiotoca lateralis

1972 ◽  
Vol 29 (11) ◽  
pp. 1543-1553 ◽  
Author(s):  
P. W. Webb ◽  
J. R. Brett
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Oxygen Tension ◽  
Flow Rate ◽  
Oxygen Transfer ◽  
Blood Flow Rate ◽  
Unit Weight ◽  
Ovarian Fluid ◽  
Transfer Characteristics ◽  
Embiotoca Lateralis

Oxygen tension and content of intraovarian fluid were measured for the viviparous pile perch, Rhacochilus vacca, during middle and late gestation. Oxygen tension decreased with increasing demands of the brood, reaching a minimum of 13.7 mm Hg just prior to parturition. Total oxygen content of the ovarian fluid decreased to a minimum of 22 mg O2, rising thereafter to 54 mg O2 at parturition as the volume of ovarian fluid increased. The in vitro oxygen consumption of the young per unit weight increased 2.5 times during gestation reaching 222 mg O2/kg/hr at birth (mean weight 3.8 g).Oxygen consumption of two pregnant striped seaperch, Embiotoca lateralis, was fairly constant at 70 mg O2/kg/hr early in gestation, increasing later to approximately 107 mg O2/kg/hr at parturition.An oxygen dissociation curve was determined for ventricular blood of pregnant pile perch. The p50 was 12.5 mm Hg. Along with other parameters, this was used to estimate the oxygen transfer characteristics of the brood–ovary exchange system, maximum possible oxygen consumption, and ovarian blood flow rate. The capacity of the system to meet the increasing requirements of the young decreased during gestation, reaching limiting conditions at parturition. It was concluded that transfer of oxygen to the young would be controlled by, and ultimately limited by, ovarian blood flow rate. The brood–ovary system is compared with the mammalian placenta.

The Effect of Furosemide on the Intrarenal Blood Flow Distribution in the Dog

1972 ◽  
Vol 50 (8) ◽  
pp. 774-783 ◽  
Author(s):  
Serge Carrière ◽  
Michel Desrosiers ◽  
Jacques Friborg ◽  
Michèle Gagnan Brunette
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Urine Volume ◽  
Flow Distribution ◽  
Blood Flow Rate ◽  
Initial Distribution ◽  
Blood Flow Distribution ◽  
Intrarenal Blood Flow ◽  
Femoral Blood ◽  
Furosemide Administration

Furosemide (40 μg/min) was perfused directly into the renal artery of dogs in whom the femoral blood pressure was reduced (80 mm Hg) by aortic clamping above the renal arteries. This maneuver, which does not influence the intrarenal blood flow distribution, produced significant decreases of the urine volume, natriuresis, Ccreat, and CPAH, and prevented the marked diuresis normally produced by furosemide. Therefore the chances that systemic physiological changes occurred, secondary to large fluid movements, were minimized. In those conditions, however, furosemide produced a significant increase of the urine output and sodium excretion in the experimental kidney whereas Ccreat and CPAH were not affected. The outer cortical blood flow rate (ml/100 g-min) was modified neither by aortic constriction (562 ± 68 versus 569 ± 83) nor by the subsequent administration of furosemide (424 ± 70). The blood flow rate of the outer medulla in these three conditions remained unchanged (147 ± 52 versus 171 ± 44 versus 159 ± 54). The initial distribution of the radioactivity in each compartment remained comparable in the three conditions. In parallel with the results from the krypton-85 disappearance curves, the autoradiograms, silicone rubber casts, and EPAH did not suggest any change in the renal blood flow distribution secondary to furosemide administration.

The Effect of Hematocrit on the Clearance of Small Molecules during Hemodialysis

1983 ◽  
Vol 6 (3) ◽  
pp. 127-130 ◽  
Author(s):  
C. Woffindin ◽  
N.A. Hoenich ◽  
D.N.S. Kerr
Keyword(s):  
Blood Flow ◽  
Regression Analysis ◽  
Small Molecules ◽  
Flat Plate ◽  
Flow Rate ◽  
Distribution Curve ◽  
Blood Flow Rate ◽  
Hollow Fibre ◽  
Urea Clearance ◽  
Flow Rates

Data collected during the evaluation of a series of hemodialysers were analysed to see the effect of hematocrit on the clearance of urea and creatinine. All evaluations were performed on patients with a range of hematocrits with a mean close to 20%. The urea clearance of those in the upper half of the distribution curve (mean hematocrit 29.4%) was not significantly different from that of patients in the lower half of the distribution curve (mean hematocrit 16.9%) whether the clearance was studied at high or low blood flow rates and with hollow fibre or flat plate disposable hemodialysers. Likewise, there was no correlation between hematocrit and urea clearance by regression analysis. In contrast, the clearance of creatinine was affected by hematocrit being greater at lower hematocrit values. This difference was independent of blood flow rate and dialyser type and was confirmed by regression analysis.

Sign in / Sign up

Export Citation Format

Share Document