Effects of temperature on acid-base balance and ventilation in desert iguanas

1981 ◽  
Vol 51 (2) ◽  
pp. 452-460 ◽  
Author(s):  
P. E. Bickler

The effects of constant and changing temperatures on blood acid-base status and pulmonary ventilation were studied in the eurythermal lizard Dipsosaurus dorsalis. Constant temperatures between 18 and 42 degrees C maintained for 24 h or more produced arterial pH changes of -0.0145 U X degrees C-1. Arterial CO2 tension (PCO2) increased from 9.9 to 32 Torr plasma [HCO-3] and total CO2 contents remained constant at near 19 and 22 mM, respectively. Under constant temperature conditions, ventilation-gas exchange ratios (VE/MCO2 and VE/MO2) were inversely related to temperature and can adequately explain the changes in arterial PCO2 and pH. During warming and cooling between 25 and 42 degrees C arterial pH, PCO2 [HCO-3], and respiratory exchange ratios (MCO2/MO2) were similar to steady-state values. Warming and cooling each took about 2 h. During the temperature changes, rapid changes in lung ventilation following steady-state patterns were seen. Blood relative alkalinity changed slightly with steady-state or changing body temperatures, whereas calculated charge on protein histidine imidazole was closely conserved. Cooling to 17-18 degrees C resulted in a transient respiratory acidosis correlated with a decline in the ratio VE/MCO2. After 12-24 h at 17-18 degrees C, pH, PCO2, and VE returned to steady-state values. The importance of thermal history of patterns of acid-base regulation in reptiles is discussed.

1977 ◽  
Vol 232 (1) ◽  
pp. R10-R17 ◽  
Author(s):  
R. G. DeLaney ◽  
S. Lahiri ◽  
R. Hamilton ◽  
P. Fishman

Upon entering into aestivation, Protopterus aethiopicus develops a respiratory acidosis. A slow compensatory increase in plasma bicarbonate suffices only to partially restore arterial pH toward normal. The cessation of water intake from the start of aestivation results in hemoconcentration and marked oliguria. The concentrations of most plasma constituents continue to increase progressively, and the electrolyte ratios change. The increase in urea concentration is disproportionately high for the degree of dehydration and constitutes an increasing fraction of total plasma osmolality. Acid-base and electrolyte balance do not reach a new equilibrium within 1 yr in the cocoon.


1976 ◽  
Vol 230 (3) ◽  
pp. 608-613 ◽  
Author(s):  
G Gottlieb ◽  
DC Jackson

Pulmonary and cutaneous O2 consumption (Vo2) and CO2 production (Vco2) were measured simultaneously in bullfrogs Rana catesbeiana at 20 degrees C. The lungs were responsible for 77.3-91.0% of the total Vo2 and 28.5-74.9% of the total VCO2. The distribution of the total exchange between the lungs and skin depended on metabolic rate; frogs with higher rates relied more heavily on the pulmonary mode for both Vo2 and Vco2. When prevented from ventilating their lungs in an O2-rich environment, bullfrogs developed severe respiratory acidosis, demonstrating the importance of lung exchange in normal acid-base balance. When frogs were totally submerged in an O2-saturated medium, skin Vco2 increased linearly to a steady-state value which approximated the preapneic total Vco2. In these same animals, arterial Pco2 increased proportionately to the increase in skin Vco2, indicating that skin diffusion capacity for CO2 was unaffected. We conclude that the control of breathing in the bullfrog in response to changes in metabolic rate relies predominantly on changes in lung ventilation while the skin plays a more passive role.


1962 ◽  
Vol 23 (1) ◽  
pp. 158-159
Author(s):  
F. E. NOE ◽  
E. SEKINO ◽  
F. E. GREIFENSTEIN

1980 ◽  
Vol 84 (1) ◽  
pp. 289-302
Author(s):  
R. G. Boutilier ◽  
D. G. McDonald ◽  
D. P. Toews

A combined respiratory and metabolic acidosis occurs in the arterial blood immediately following 30 min of strenuous activity in the predominantly skin-breathing urodele, Cryptobranchus alleganiensis, and in the bimodal-breathing anuran, Bufo marinus, at 25 degrees C. In Bufo, the bulk of the post-exercise acidosis is metabolic in origin (principally lactic acid) and recovery is complete within 4-8 h. In the salamander, a lower magnitude, longer duration, metabolic acid component and a more pronounced respiratory acidosis prolong the recovery period for up to 22 h post-exercise. It is suggested that fundamental differences between the dominant sites for gas exchange (pulmonary versus cutaneous), and thus in the control of respiratory acid-base balance, may underline the dissimilar patterns of recovery from exercise in these two species.


1957 ◽  
Vol 3 (5) ◽  
pp. 631-637
Author(s):  
Herbert P Jacobi ◽  
Anthony J Barak ◽  
Meyer Beber

Abstract The Co2 combining power bears a variable relationship to the in vivo plasma bicarbonate concentration, depending upon the type and severity of acid-base distortion. In respiratory alkalosis and metabolic acidosis the Co2 combining power will usually be greater than the in vivo plasma bicarbonate concentration; whereas, in respiratory acidosis and metabolic alkalosis the Co2 combining power will usually be less. Co2 content, on the other hand, will always parallel the in vivo plasma bicarbonate concentration quite closely, being only slightly greater. These facts, together with other considerations which are discussed, recommend the abandonment of the determination of CO2 combining power.


1987 ◽  
Vol 253 (3) ◽  
pp. G330-G335
Author(s):  
D. S. Goldfarb ◽  
P. M. Ingrassia ◽  
A. N. Charney

We previously reported that systemic pH and HCO3 concentration affect ileal water and electrolyte absorption. To determine whether these effects could influence an ongoing secretory process, we measured transport in ileal loops exposed to either saline or 50-75 micrograms cholera toxin in mechanically ventilated Sprague-Dawley rats anesthetized with pentobarbital sodium. The effects of acute respiratory and metabolic acidosis and alkalosis were then examined. Decreases in systemic pH during respiratory acidosis caused equivalent increases in net water (54 +/- 8 microliters . cm-1 . h-1) and Na absorption (7 +/- 1 mu eq . cm- . h-1) and smaller increases in Cl absorption in cholera toxin compared with saline loops. These increases reversed the net secretion of these ions observed during alkalemia in the cholera toxin loops to net absorption. Metabolic acidosis and alkalosis and respiratory compensation of systemic pH of these metabolic disorders also altered cholera toxin-induced secretion in a direction consistent with the pH change. The increase in net HCO3 secretion caused by cholera toxin was unaffected by the respiratory disorders and did not vary with the HCO3 concentration in the metabolic disorders. These findings suggest that the systemic acid-base disorders that characterize intestinal secretory states may themselves alter intestinal absorptive function and fluid losses.


1985 ◽  
Vol 1 (4) ◽  
pp. 259-277 ◽  
Author(s):  
John W. Severinghaus ◽  
Poul B. Astrup

2015 ◽  
Vol 18 (1) ◽  
pp. 217-222 ◽  
Author(s):  
P. Sławuta ◽  
K. Glińska-Suchocka ◽  
A. Cekiera

AbstractApart from the HH equation, the acid-base balance of an organism is also described by the Stewart model, which assumes that the proper insight into the ABB of the organism is given by an analysis of: pCO2, the difference of concentrations of strong cations and anions in the blood serum – SID, and the total concentration of nonvolatile weak acids – Acid total. The notion of an anion gap (AG), or the apparent lack of ions, is closely related to the acid-base balance described according to the HH equation. Its value mainly consists of negatively charged proteins, phosphates, and sulphates in blood. In the human medicine, a modified anion gap is used, which, including the concentration of the protein buffer of blood, is, in fact, the combination of the apparent lack of ions derived from the classic model and the Stewart model. In brachycephalic dogs, respiratory acidosis often occurs, which is caused by an overgrowth of the soft palate, making it impossible for a free air flow and causing an increase in pCO2– carbonic acid anhydride The aim of the present paper was an attempt to answer the question whether, in the case of systemic respiratory acidosis, changes in the concentration of buffering ions can also be seen. The study was carried out on 60 adult dogs of boxer breed in which, on the basis of the results of endoscopic examination, a strong overgrowth of the soft palate requiring a surgical correction was found. For each dog, the value of the anion gap before and after the palate correction procedure was calculated according to the following equation: AG = ([Na+mmol/l] + [K+mmol/l]) – ([Cl−mmol/l]+[HCO3−mmol/l]) as well as the value of the modified AG – according to the following equation: AGm= calculated AG + 2.5 × (albuminsr– albuminsd). The values of AG calculated for the dogs before and after the procedure fell within the limits of the reference values and did not differ significantly whereas the values of AGmcalculated for the dogs before and after the procedure differed from each other significantly. Conclusions: 1) On the basis of the values of AGmobtained it should be stated that in spite of finding respiratory acidosis in the examined dogs, changes in ion concentration can also be seen, which, according to the Stewart theory, compensate metabolic ABB disorders 2) In spite of the fact that all the values used for calculation of AGmwere within the limits of reference values, the values of AGmin dogs before and after the soft palate correction procedure differed from each other significantly, which proves high sensitivity and usefulness of the AGmcalculation as a diagnostic method.


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