Carbon dioxide governs the oxygen affinity of crocodile blood

Nature ◽  
1977 ◽  
Vol 269 (5631) ◽  
pp. 825-827 ◽  
Author(s):  
CHRISTIAN BAUER ◽  
WOLFGANG JELKMANN
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Affinity ◽  
Crocodile Blood

scholarly journals Oxygen and Carbon Dioxide Transport Characteristics of the Blood of the Nile Monitor Lizard (Varanus Niloticus)

1987 ◽  
Vol 130 (1) ◽  
pp. 27-38
Author(s):  
JAMES W. HICKS ◽  
ATSUSHI ISHIMATSU ◽  
NORBERT HEISLER
Keyword(s):  
Carbon Dioxide ◽  
Haemoglobin Concentration ◽  
Oxygen Affinity ◽  
Total Blood ◽  
Carbon Dioxide Transport ◽  
Monitor Lizard ◽  
The Right ◽  
Dissociation Curves

Oxygen and carbon dioxide dissociation curves were constructed for the blood of the Nile monitor lizard, Varanus niloticus, acclimated for 12h at 25 and 35°C. The oxygen affinity of Varanus blood was low when Pco2 w a s in the range of in vivo values (25°C: P50 = 34.3 at PCOCO2 = 21 mmHg; 35°C: P50 = 46.2 mmHg at PCOCO2 = 35 mmHg; 1 mmHg = 133.3 Pa), and the oxygen dissociation curves were highly sigmoidal (Hill's n = 2.97 at 25°C and 3.40 at 35°C). The position of the O2 curves was relatively insensitive to temperature change with an apparent enthalpy of oxygenation (ΔH) of −9.2kJ mol−1. The carbon dioxide dissociation curves were shifted to the right with increasing temperature by decreasing total CCOCO2 at fixed PCOCO2, whereas the state of oxygenation had little effect on total blood CO2 content. The in vitro buffer value of true plasma (Δ[HCO3−]pl/-ΔpHpl) rose from 12.0 mequiv pH−1−1 at 25°C to 17.5 mequiv pH−11−1 at 35°C, reflecting a reversible increase of about 30% in haemoglobin concentration and haematocrit levels during resting conditions in vivo.

scholarly journals Haemoglobin function in intact lamprey erythrocytes: interactions with membrane function in the regulation of gas transport and acid-base balance.

1995 ◽  
Vol 198 (12) ◽  
pp. 2423-2430 ◽  
Author(s):  
M Nikinmaa ◽  
S Airaksinen ◽  
L V Virkki
Keyword(s):  
Carbon Dioxide ◽  
Gas Transport ◽  
Oxygen Affinity ◽  
Oxygen Binding ◽  
Acid Base Balance ◽  
Acid Base ◽  
Red Cell Membrane ◽  
Membrane Function ◽  
Acid And Base ◽  
Base Balance

Haemoglobin function within lamprey erythrocytes offers a unique solution to gas transport among vertebrates. Lamprey haemoglobin within intact erythrocytes is in oligomer/monomer equilibrium and has an oxygen affinity similar to that of haemoglobin in other active fishes. The cooperativity of oxygen binding, which is reduced at low pH values, the effect of protons and the effect of the concentration of haemoglobin on its oxygen affinity are all due to dissociation/association reactions of the haemoglobin molecules. The permeability of the lamprey red cell membrane to acid and base equivalents is very low, and plasma bicarbonate cannot therefore be dehydrated to carbon dioxide to any significant extent during the residence time of blood in the gills. This potential limitation on carbon dioxide excretion is overcome, however, by the high intraerythrocytic pH and the marked oxygenation-linked pH changes in the erythrocyte, which are due to the large Haldane effect of the haemoglobin. Owing to the relative impermeability of the erythrocyte membrane to acid equivalents, intraerythrocytic haemoglobin cannot take part in the acid-base buffering of the extracellular compartment. As a consequence, extracellular acid loads cause marked fluctuations in plasma pH.

Carbon Dioxide Transportation and Haemoglobin Oxygen Affinity during Haemodilution

1980 ◽  
Vol 12 (4) ◽  
pp. 242-247
Author(s):  
J. Jalonen ◽  
O. Meretoja ◽  
J. Niinikoski
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Affinity

scholarly journals Oxygen and carbon dioxide transport in vertebrate erythrocytes: an evolutionary change in the role of membrane transport.

1997 ◽  
Vol 200 (2) ◽  
pp. 369-380 ◽  
Author(s):  
M Nikinmaa
Keyword(s):  
Carbon Dioxide ◽  
Teleost Fish ◽  
Oxygen Affinity ◽  
Carbon Dioxide Tension ◽  
Buffering Capacity ◽  
Proton Efflux ◽  
Carbon Dioxide Transport ◽  
Elasmobranch Fish ◽  
Haldane Effect

Two major strategies are apparent for the regulation of gas transport by vertebrate blood except in the myxinoids, which seem to have little scope for such regulation. In lampreys and teleost fish, haemoglobins have low buffering capacities and large Bohr/Haldane effects. Na+/H+ exchange plays an important role in the control of haemoglobin oxygen-affinity in these vertebrate groups. The large Bohr/Haldane effect also facilitates carbon dioxide transport: the blood (or erythrocyte) pH increases upon deoxygenation, thus increasing the concentration of bicarbonate formed at a given carbon dioxide tension. In lampreys, the bicarbonate permeability of the erythrocyte membrane is low. As a consequence, extracellular acid loads cannot be buffered by haemoglobin. In contrast, teleost erythrocytes possess a functional anion exchange, allowing extracellular proton loads to be buffered by haemoglobin. However, because the buffering capacity of teleost haemoglobins is low, buffering of extracellular acid loads is less effective in teleost fish than in elasmobranch fish and in air-breathing vertebrates whose haemoglobins have a high buffering capacity. However, the high buffering capacity of the haemoglobins diminishes the possibility of regulating haemoglobin oxygen-affinity via secondarily active Na+/H+ exchange, because intracellular pH changes, caused by proton efflux, remain small.

The Effect of Hemolysis Upon the Oxygen Affinity of Hemoglobin in the Atlantic (Salmo salar) and Landlocked Salmon (Salmo salar sebago)

1966 ◽  
Vol 23 (10) ◽  
pp. 1575-1580 ◽  
Author(s):  
Edgar C. Black ◽  
Harold H. Tucker ◽  
Donald Kirkpatrick
Keyword(s):  
Carbon Dioxide ◽  
Salmo Salar ◽  
Oxygen Affinity ◽  
Bohr Effect ◽  
Consistent Difference ◽  
Winter Conditions ◽  
Oxygen Affinity Of Hemoglobin

Confirming the work of other investigators, hemolysis was shown to diminish the influence exerted by carbon dioxide upon the affinity of oxygen for hemoglobin (Bohr effect). There was no consistent difference between blood taken from salmon acclimated to summer and winter conditions. Furthermore, there was no consistent difference between the effect of hemolysis on the Bohr effect between Atlantic and landlocked salmon.

Respiratory pigments: interactions between oxygen and carbon dioxide transport

1989 ◽  
Vol 67 (12) ◽  
pp. 2971-2985 ◽  
Author(s):  
C. R. Bridges ◽  
S. Morris
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Venous Blood ◽  
Oxygen Affinity ◽  
Specific Effect ◽  
Carbon Dioxide Transport ◽  
Wide Range ◽  
Lower Vertebrates ◽  
Haldane Effect

Oxygen and carbon dioxide are transported in vertebrates and invertebrates by a wide range of respiratory pigments. These respiratory gases are not transported independently of one another, and this review considers the influence of carbon dioxide on oxygen transport and vice versa. A specific effect of carbon dioxide or bicarbonate, decreasing oxygen affinity, is found in many haemoglobins, but the effect is often reduced in the presence of organic phosphates. Clear experimental data are available for mammalian haemoglobins but in birds and lower vertebrates more data are required to verify the presence and magnitude of the CO2 effect. In erythrocruorins and haemocyanins CO2 increases O2 affinity, whereas in haemerythrins, as in haemoglobin, CO2 again decreases oxygen affinity. Much of our knowledge of invertebrate respiratory pigments is based, however, on data from one or two species. A specific effect of CO2 on O2 affinity has also often been found only at high CO2 partial pressures, which may be outside the physiological range for these species. More in vivo experimental data on CO2 values are required for these species, and further studies on other species may help to explain this discrepancy. The interaction of O2 and CO2 transport is mainly through the Haldane effect, i.e., deoxygenated blood having a greater capacity for CO2 than oxygenated blood. This is due directly to the formation of carbamino groups (carbamate) and also to the fact that deoxygenated blood binds relatively more protons than oxygenated blood. This forms the basis for the linkage between the Bohr and Haldane effects. In some species in which the Bohr coefficient is below −1.0, an akalosis in the tissues may be induced. Large Haldane effects may be particularly effective in promoting CO2 unloading when the partial pressure difference of CO2 between arterial and venous blood is small. Carbamate formation may account for 10–20% of the CO2 transported in mammals, but its role in lower vertebrates and invertebrates has only recently been considered. Carbon dioxide transport is modulated by those factors that influence O2 affinity as these in turn influence the Haldane effect.

The Oxygen Affinities of Certain Invertebrate Haemoglobins

1945 ◽  
Vol 21 (3-4) ◽  
pp. 161-164
Author(s):  
H. MUNRO FOX
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Pressure ◽  
Oxygen Affinity ◽  
Carbon Dioxide Concentration ◽  
Small Sample ◽  
The Body ◽  
Coelomic Fluid ◽  
Human Haemoglobin ◽  
Invertebrate Animals ◽  
Planorbis Corneus

1. A method is described for measuring the oxygen affinity of haemoglobin in small sample of whole or slightly diluted blood or coelomic fluid. 2. The oxygen affinity of the haemoglobins of the following invertebrate animals is high: Chironomus riparius, Tubifex sp., Ceriodaphnia laticaudata, Thalassema neptuni, Arenicola marina, Planorbis corneus, Daphnia magna. The oxygen pressure in millimetres of mercury for 50% oxyhaemoglobin at 17° C. in the absence of carbon dioxide varies, in the order of species just given, from 0.6 for Chironomus to 3.1 for Daphnia. This may be compared with 27 for human whole blood at 20° C. and pH 7.4. 3. A carbon dioxide concentration of 1% of an atmosphere has no measurable effect on the oxygen affinity of Chironomus haemoglobin. In the other invertebrates studied this concentration of carbon dioxide increases the oxygen affinity by about 1½ times, which is less than half its effect on human haemoglobin. 4. When the haemoglobins of Tubifex, Chirononmus, Daphnia and Planorbis are becoming deoxygenated in the animal there is a much lower oxygen pressure in the blood than in the water outside the animal. This means a steep gradient of oxygen pressure across the body wall. Consequently, for the animal to pick up oxygen from water containing little, but still considerable, quantities of the gas, haemoglobin of high oxygen affinity is essential.

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