Facilitation by Carbonic Anhydrase of Carbon Dioxide Transport

Science ◽  
1967 ◽  
Vol 155 (3758) ◽  
pp. 44-47 ◽  
Author(s):  
T. Enns
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Anhydrase ◽  
Carbon Dioxide Transport

The Physiology of Carbon Dioxide Transport in Insect Blood

1950 ◽  
Vol 27 (2) ◽  
pp. 184-191 ◽  
Author(s):  
L. LEVENBOOK
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Anhydrase ◽  
Respiratory System ◽  
Buffer Capacity ◽  
Carbon Dioxide Transport ◽  
Capacity Curves ◽  
Titration Data

1. From titration data it has been calculated that the buffer capacity β for normal Gastrophilus blood at pH 6.8 is 0.0225, for dialysed blood 0.014 and for blood to which carbonic anhydrase has been added, 0.033. The buffer capacity curves are all more or less U-shaped. 2. The contribution towards the total buffer capacity of various buffering substances, of which protein and bicarbonate are the most important, has been quantitatively determined. 3. It is tentatively suggested that the reason why insect blood is better buffered on either side of its normal pH instead of the reverse as in other animals, may be related to the inefficiency of the tracheal respiratory system in eliminating excess CO2.

scholarly journals CLINICAL SIGNIFICANCE OF CARDIAC AND RESPIRATORY ADJUSTMENTS IN CHRONIC ANEMIA

Blood ◽  
1948 ◽  
Vol 3 (4) ◽  
pp. 329-348 ◽  
Author(s):  
HERRMAN L. BLUMGART ◽  
MARK D. ALTSCHULE
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Carbonic Anhydrase ◽  
Carrying Capacity ◽  
Vital Capacity ◽  
The Body ◽  
Carbon Dioxide Transport ◽  
Chronic Anemia ◽  
Arterial Blood ◽  
Oxygen Carrying Capacity

Abstract The cardiac and respiratory adjustments in chronic anemia and their clinical manifestations have been reviewed. When the oxygen carrying capacity of the blood is diminished, an adequate supply of oxygen to the tissues is maintained by an increased cardiac output, an increased velocity of blood flow, and a relatively more complete abstraction of the oxygen from the blood as it passes through the capillaries. With the increased blood flow, the average peripheral resistance is decreased but the state of the small blood vessels is not uniform everywhere; the blood flow in the hands and kidneys, for instance, may be reduced, while that of other parts of the body is increased. The total oxygen consumption of the body in anemia is not strikingly altered. The blood volume generally is slightly reduced but the plasma volume is normal. The deviations from the normal values vary from patient to patient, but generally are definite when the hemoglobin values are less than 50 per cent and are greatest at the lowest levels of hemoglobin concentration. The close interrelationship between the cardiovascular and respiratory systems is exemplified by the coincident changes in the respiratory system in anemia. The rate and depth of respiration often are increased together with a lowering in the vital capacity and its subdivisions, the reserve and complemental air volumes. The resid- ual air is somewhat increased. These deviations from the normal are similar to those observed in pulmonary congestion or edema and denote a loss of elasticity and expansibility favoring the occurrence of exertional dyspnea. The arterial blood saturation is usually normal at rest but, during exertion, a significant lowering becomes apparent. The importance of hemoglobin in the transport of carbon dioxide is reviewed; the decreased availability of hemoglobin as a buffer in carbon dioxide transport in anemia is compensated by the increased ventilation of the blood in the lungs, rendering the arterial blood somewhat alkalotic. The red cells also play an important role in regard to the respiratory enzyme, carbonic anhydrase. In the anemias due to blood loss, malnutrition, chronic infection, uremia, or leukemia, the blood carbonic anhydrase activity is parallel to the decrease in hemoglobin level leading to a deficiency not only of oxygen carrying capacity but also a decreased ability to absorb carbon dioxide from the tissues and to release it in the lungs. The following factors, many of which are closely interrelated, are operative in the production of dyspnea in anemic patients: the increased respiratory minute volume, the decreased vital capacity and its subdivisions, the abnormalities in carbon dioxide transport and dissociation, the reduced arterial oxygen capacity and the decreased blood oxygen saturation during effort, and the frequently observed elevated blood lactic acid values. The symptoms and signs exhibited by anemic patients, including palpitation and breathlessness on exertion, tachycardia, cardiac dilatation and hypertrophy, are described. In addition to an apical systolic murmur, other systolic and diastolic murmurs are occasionally heard. The arterial blood pressure is frequently lowered in anemia; the venous pressure is generally within the limits of normal. Electrocardiographic abnormalities occur in approximately one-quarter of anemic patients but are minor and not specific in character. The occurrence of angina pectoris, congestive failure, and intermittent claudication in some patients with the development of anemia, and disappearance of these conditions as the anemia is alleviated, is discussed with particular reference to the underlying physiologic mechanisms.

Relative effects of carbonic anhydrase infusion or inhibition on carbon dioxide transport and acid-base status in the sea lamprey Petromyzon marinus following exercise

1996 ◽  
Vol 199 (4) ◽  
pp. 933-940
Author(s):  
B Tufts ◽  
S Currie ◽  
J Kieffer
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Anhydrase ◽  
Venous Blood ◽  
Extracellular Fluid ◽  
Respiratory Acidosis ◽  
Acid Base ◽  
Carbon Dioxide Transport ◽  
Co2 Transport ◽  
Arterial Blood ◽  
Acid Base Status

In vivo experiments were carried out to determine the relative effects of carbonic anhydrase (CA) infusion or inhibition on carbon dioxide (CO2) transport and acid-base status in the arterial and venous blood of sea lampreys recovering from exhaustive exercise. Infusion of CA into the extracellular fluid did not significantly affect CO2 transport or acid-base status in exercised lampreys. In contrast, infusion of the CA inhibitor acetazolamide resulted in a respiratory acidosis in the blood of recovering lampreys. In acetazolamide-treated lampreys, the post-exercise extracellular pH (pHe) of arterial blood was significantly lower than that in the saline-infused (control) lampreys. The calculated arterial and venous partial pressure of carbon dioxide (PCO2) and the total CO2 concentration in whole blood (CCO2wb) and red blood cells (CCO2rbc) during recovery in the acetazolamide-infused lampreys were also significantly greater than those values in the saline-infused control lampreys. These results suggest that the CO2 reactions in the extracellular compartment of lampreys may already be in equilibrium and that the access of plasma bicarbonate to CA is probably not the sole factor limiting CO2 transport in these animals. Furthermore, endogenous red blood cell CA clearly has an important role in CO2 transport in exercising lampreys.

Effect of water activity on carbon dioxide transport in cholinium-based ionic liquids with carbonic anhydrase

2016 ◽  
Vol 168 ◽  
pp. 74-82 ◽  
Author(s):  
C.F. Martins ◽  
L.A. Neves ◽  
M. Estevão ◽  
A. Rosatella ◽  
V.D. Alves ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ionic Liquids ◽  
Carbonic Anhydrase ◽  
Water Activity ◽  
Carbon Dioxide Transport ◽  
Effect Of Water

Carbon dioxide transport in anesthetized dogs during inhibition of carbonic anhydrase

1961 ◽  
Vol 16 (6) ◽  
pp. 1023-1028 ◽  
Author(s):  
Stephen M. Cain ◽  
Arthur B. Otis
Keyword(s):  
Carbon Dioxide ◽  
Steady State ◽  
Carbonic Anhydrase ◽  
The Other ◽  
Pure Oxygen ◽  
Carbon Dioxide Transport ◽  
Carbon Dioxide Output ◽  
Initial Control ◽  
Anesthetized Dogs ◽  
Mixed Venous

Following inhibition of blood carbonic anhydrase by acetazolamide in anesthetized dogs with one lung rebreathing in connection with a bag and with the other lung ventilating freely on pure oxygen, mixed venous Pco2 increased and alveolar Pco2 decreased. Carbon dioxide output dropped initially but gradually rose and attained a steady state value equal to that of the initial control condition. Before acetazolamide, 19% of the pulmonary CO22 output was derived from dissolved CO2, 26% from carbamino compound, and 55% from bicarbonate. In the new steady state following acetazolamide, 45% came from dissolved CO2, 38% from carbamino, and 17% from bicarbonate. Submitted on June 12, 1961

The Physiology of Carbon Dioxide Transport in Insect Blood

1950 ◽  
Vol 27 (2) ◽  
pp. 175-183
Author(s):  
L. LEVENBOOK ◽  
A. M. CLARK
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Anhydrase ◽  
Colorimetric Method ◽  
Carbon Dioxide Transport

1. A manometric and an improved colorimetric method have been employed to study the effect of insect blood on the reaction between carbon dioxide and water. 2. The absence of carbonic anhydrase from insect blood has been confirmed. 3. Neither Locust nor Gastrophilus larva blood contains any substance which inhibits the hydration of carbon dioxide.

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