The effects of hypercapnia on intracellular and extracellular acid-base status in the toad Bufo marinus

1982 ◽  
Vol 97 (1) ◽  
pp. 79-86
Author(s):  
D. P. Toews ◽  
N. Heisler
Keyword(s):  
Extracellular Space ◽  
Environmental Water ◽  
Bufo Marinus ◽  
Acid Base ◽  
Relative Preference ◽  
Base Parameters ◽  
Initial Drop ◽  
Acid Base Status ◽  
Body Compartments ◽  
Induced Changes

Toads (Bufo marinus) were exposed to environmental hypercapnia of 5% CO2 in air, and extracellular and intracellular acid-base parameters were determined 1 and 24 h after the onset of hypercapnia. The initial drop in pH was compensated by the elevation of extracellular and intracellular bicarbonate. Relating the pH compensation to the pH drop that is expected to occur by increased PCO2 at constant bicarbonate concentration, the pH compensation in the extracellular space was 30% and reached the following values for intracellular body compartments: 65% in skeletal muscle, 77% in heart muscle and 44% in skin. The additional bicarbonate was partly produced by blood and intracellular non-bicarbonate buffers; the major portion of the remainder was related to the excretion of ammonia into the environmental water. The hypercapnia-induced changes of pH were considerably smaller in all tissue cells than in the extracellular space. Thus Bufo marinus exhibits the relative preference of intracellular over extracellular acid-base regulation that has been observed in other vertebrates.

scholarly journals Acid-Base Regulation in the Atlantic Hagfish Myxine Glutinosa

1991 ◽  
Vol 161 (1) ◽  
pp. 201-215 ◽  
Author(s):  
D. G. McDONALD ◽  
V. CAVDEK ◽  
L. CALVERT ◽  
C. L. MLLLIGAN
Keyword(s):  
Sulphuric Acid ◽  
Blood Volume ◽  
Ammonium Sulphate ◽  
Extracellular Space ◽  
External Environment ◽  
Buffering Capacity ◽  
Acid Excretion ◽  
Acid Base ◽  
Myxine Glutinosa ◽  
Acid Base Status

Blood acid-base status and net transfers of acidic equivalents to the external environment were studied in hagfish, Myxine glutinosa, infused with ammonium sulphate (4mequivkg−1 NH4+) or with sulphuric acid (3mequiv kg−1 H+). Hagfish extracellular fluids (ECF) play a greater role in acid-base regulation than in teleosts. This is because hagfish have a much larger blood volume relative to teleosts, despite a relatively low blood buffering capacity. Consequently, infusion of ammonium sulphate produced only half of the acidosis produced in marine teleosts in comparable studies, and hagfish readily tolerated a threefold greater direct H+ load. Furthermore, the H+ load was largely retained and buffered in the extracellular space. Despite smaller acid-base disturbances, rates of net H+ excretion to the external environment were, nonetheless, comparable to those of marine teleosts, and net acid excretion persisted until blood acid-base disturbances were corrected. We conclude that the gills of the hagfish are at least as competent for acid-base regulation as those of marine teleosts. The nature of the H+ excretion mechanism is discussed.

Effects of temperature and acid-base state on hippocampal population spikes in hamsters

1990 ◽  
Vol 258 (5) ◽  
pp. R1140-R1146 ◽  
Author(s):  
P. Eckerman ◽  
K. Scharruhn ◽  
J. M. Horowitz
Keyword(s):  
Hippocampal Slices ◽  
Pyramidal Cells ◽  
Effect Of Temperature ◽  
Acid Base ◽  
Bathing Medium ◽  
Maximal Stimulation ◽  
Synchronous Firing ◽  
Acid Base Status ◽  
Effects Of Temperature ◽  
Induced Changes

Previous studies have shown that changes in temperature, within the range encountered by hamsters entering hibernation, alter the evoked response of hippocampal pyramidal cells to stimulation of an afferent pathway. The present study was designed to determine whether these alterations are due to changes in the acid-base status of the neural tissue brought about by changes in temperature. Extracellular-evoked responses were recorded from hamster hippocampal slices after Schaffer collateral stimulation. The pH was changed by varying the concentration of CO2 aerating the bathing medium. Buffers contained either 26 or 40 mM bicarbonate ion. The width of the population spike (the synchronous firing of pyramidal cells) was measured as pH was varied between 7.5 and 7.1, with slice temperature set at either 25 or 20 degrees C. There was a significant increase in spike width as temperature was lowered to 20 degrees C, but no significant change in spike width or amplitude as pH or bicarbonate was varied. The effect of temperature (20 degrees C for half-maximal stimulation, and from 20 to 25 degrees C for just maximal stimulation) on spike width and amplitude thus does not appear to be due to pH- or bicarbonate-induced changes.

Discordant Twins: Acid-Base Status

1991 ◽  
Vol 40 (3-4) ◽  
pp. 373-381 ◽  
Author(s):  
S.A. Ordorica ◽  
F.J. Frieden ◽  
I.A. Hoskins ◽  
B.K. Young
Keyword(s):  
Birth Weight ◽  
Acid Base ◽  
Apgar Scores ◽  
Twin Birth ◽  
Umbilical Blood ◽  
Base Parameters ◽  
Acid Base Status ◽  
Discordant Twins ◽  
A Prospective Study ◽  
Paired T Test

AbstractA prospective study was undertaken to determine the effect of twin birth-weight discordancy on Apgar scores and umbilical blood acid-base parameters. Using the paired t-test, small but statistically significant differences were seen in these parameters favoring the heavier twin over its lighter sibling. These differences were also affected by birth order, with the first-born being favored.

scholarly journals The importance of metabolism in acid–base regulation and acid–base methodology

1989 ◽  
Vol 67 (12) ◽  
pp. 3005-3017 ◽  
Author(s):  
Hans-Otto Pörtner
Keyword(s):  
Integrated Control ◽  
Feedback Regulation ◽  
Urea Synthesis ◽  
Acid Base ◽  
Base Parameters ◽  
Recent Developments ◽  
Acid Base Status ◽  
The Relationship ◽  
Aerobic And Anaerobic

Metabolism not only affects the acid–base status of an animal by means of proton stoichiometries but, by feedback regulation, acid–base parameters (pH, [Formula: see text], bicarbonate) influence metabolic rates and the pathways used. This leads to a significant contribution of metabolism to acid–base regulation under both aerobic and anaerobic conditions. The relationship between amino acid metabolism, urea synthesis, and [Formula: see text] excretion is discussed as an example important for steady-state metabolic acid–base regulation during aerobiosis. Generally, acid–base relevant metabolism may be regulated through the effect of acid–base disturbances on hormonal mediation, allosteric modulation of enzyme proteins, pH optima, and the levels of substrates or products, some of these being acid–base relevant substances like bicarbonate, CO2, inorganic phosphate, and NH3. During functional or environmental anaerobiosis the same relationships prevail. Metabolic proton accumulation is counterbalanced by phosphagen depletion and ammonia accumulation in adenylate catabolism. In addition, in integrated control of metabolic and acid–base status, long-term (mitochondrial) anaerobiosis leads to reductions in metabolic rate and increased removal of acidic groups. The importance of metabolic processes in acid–base methodology is discussed in terms of traditional concepts and recent developments.

scholarly journals Anaerobic Metabolism and Changes in Acid—Base Status: Quantitative Interrelationships and PH Regulation in the Marine Worm Sipunculus Nudus

1987 ◽  
Vol 131 (1) ◽  
pp. 89-105
Author(s):  
HANS-OTTO PÖRTNER
Keyword(s):  
Anaerobic Metabolism ◽  
Ph Value ◽  
Ph Regulation ◽  
Proton Exchange ◽  
Acid Base ◽  
Base Parameters ◽  
Sipunculus Nudus ◽  
Theoretical Predictions ◽  
Acid Base Status ◽  
Proton Generation

The quantitative influence of anaerobic metabolism on acid—base status and on acid-base regulation is investigated in Sipunculus nudus L. Proton generation by metabolism is calculated from theoretical predictions. The quantitative comparison of metabolic protons with non-respiratory protons found in the acid—base status is performed assuming a simplified model of the total animal. Taking the protonequivalent ion exchange between animals and ambient water into account, changes in the anaerobic acid—base status can be explained exclusively by proton generation in metabolism. It is concluded that the classical concept of acid—base physiology is adequate and that the consideration of strong ions is not required for a quantitative treatment of the acid—base status. The hypothesis that a quantitative correlation exists between metabolic and acid—base events is tested by comparing changes in acid—base status and in metabolism in animals exhibiting different metabolic rates. For this purpose, a method is developed for the calculation of intracellular pH from metabolite concentrations and extracellular acid—base parameters. Proton exchange between intra-and extracellular compartments, which is found to depend upon the total amount of accumulated non-respiratory protons, demonstrates that pHi is regulated even during anaerobiosis. The defended pH, value, however, is lower during anaerobiosis than during subsequent recovery. Note: Address for reprint requests

scholarly journals Interaction between temperature and hypoxia in the alligator

1993 ◽  
Vol 265 (6) ◽  
pp. R1339-R1343 ◽  
Author(s):  
L. G. Branco ◽  
H. O. Portner ◽  
S. C. Wood
Keyword(s):  
Body Temperature ◽  
Blood Gases ◽  
The Body ◽  
Plasma Lactate ◽  
Acid Base ◽  
Terrestrial Vertebrates ◽  
Beneficial Response ◽  
Acid Base Status ◽  
Induced Changes ◽  
Selected Body Temperature

Hypoxia elicits behavioral hypothermia in alligators. Under normoxic conditions, the selected body temperature is 27.8 +/- 1.2 degrees C. However, when inspired O2 is lowered to 4%, selected body temperature decreases to 15.4 +/- 1.0 degrees C. The threshold for the behavioral hypothermia is between 4 and 5% inspired O2, the lowest threshold measured so far in terrestrial vertebrates. This study assessed the physiological significance of the behavioral hypothermia. The body temperature was clamped at 15, 25, and 35 degrees C for measurements of ventilation, blood gases, metabolic rate, plasma lactate, and acid-base status. Hypoxia-induced changes in ventilation, acid-base status, oxygen consumption, and lactate were proportional to body temperature, being pronounced at 35 degrees C, less at 25 degrees C, and absent at 15 degrees C. The correlation between selected body temperature under severe hypoxia and the measured parameters show that behavioral hypothermia is a beneficial response to hypoxia in alligators.

Blood Gases, and Extracellular/Intracellular Acid-Base Status as a Function of Temperature in the Anuran Amphibians Xenopus Laevis and Bufo Marinus

1987 ◽  
Vol 130 (1) ◽  
pp. 13-25 ◽  
Author(s):  
R. G. BOUTILIER ◽  
M. L. GLASS ◽  
N. HEISLER
Keyword(s):  
Xenopus Laevis ◽  
Blood Gases ◽  
Bufo Marinus ◽  
Temperature Dependent ◽  
Acid Base ◽  
Anuran Amphibians ◽  
Acid Base Status ◽  
Arterial Plasma ◽  
Tissue Compartments ◽  
Intracellular Acid

Blood gases, and parameters of the extracellular and intracellular acid-base status, were measured in the anuran amphibians Bufo marinus and Xenopus laevis acclimated to temperatures of 10, 20 and 30°C for 12 days. Arterial POO2 rose with temperature so that approximately constant oxygen saturation of the blood was maintained, a phenomenon explained on the basis of models for O2 transport in animals with central vascular shunts and temperature-dependent shifts in O2 equilibrium characteristics. Arterial plasma pH of both species varied inversely with temperature, the pH/temperature coefficient being not significantly different from that required for constant relative alkalinity or dissociation of imidazole. The change in plasma pH was brought about mainly by changes in PCOCO2 although plasma bicarbonate concentration also changed significantly. Intracellular pH/temperature relationships were found to be non-linear in most of the tissues. There was considerable variability among body tissue compartments and between the two species. These data confirm that the various tissue compartments in ectotherms maintain unique ΔpH/Δt relationships, and indicate that measurement of extracellular pH as a function of temperature is not a good indicator for alphastat-type, temperature-dependent, acid-base regulation.

Sign in / Sign up

Export Citation Format

Share Document