Quantification of pH Regulation in Hypercapnia and Hypocapnia

Bk, Siesjö

doi:10.3109/00365517109086891

Cited by 40 publications

(7 citation statements)

References 16 publications

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“…The data show that the intracellular fluids have a more efficient pH regulation than CSF and blood, and that the CSF p H is better regulated than blood p H at 45 and 180 min. Hypercapnia is associated with a similar degree of p H regulation of the intracellular fluids (SIESJO 1971), but the present results demonstrate that the regulation occurs quicker in hypocapnia. 1967).…”

Section: Glycolytic Intermediatescontrasting

confidence: 46%

Controlled Hyperventilation and Its Effect on Brain Energy and Acid‐Base Parameters

Nilsson

Busto

1973

Acta Anaesthesiol Scand

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The brain tissue concentrations of lactate, pyruvate and organic phosphates (phosphocreatine, ATP, ADP and AMP) as well as extra-and intracellular p H were determined in rats hyperventilated to Pacoe levels of 20-25 or 10-15 mmHg for periods of 10 min to 3 h. The lactate and pyruvate concentrations, and lactatelpyruvate ratios, in blood, CSF and intracellular water increased progressively with the decrease in Pco2, but a return towards normal values was observed in the 3 h groups.At moderate hypocapnia the intracellular p H was not increased significantly from the normal, but in extreme hypocapnia a net intracellular acidosis was observed. The regulation of intracellular pH in moderate hypocapnia, and the acidosis in extreme hypocapnia, was probably due to the production of metabolic acids, mainly lactic acid. However, since the concentrations of organic phosphates remained normal, the increased anaerobic production of lactic acid must have been due to other factors than a change in energy state.

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Section: Glycolytic Intermediatescontrasting

confidence: 46%

Controlled Hyperventilation and Its Effect on Brain Energy and Acid‐Base Parameters

Nilsson

Busto

1973

Acta Anaesthesiol Scand

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“…Stiffler, Tufts & Toews (1983) reported that when N. maculosus were exposed to a water P CO 2 ( P w CO 2 ) of 17.3 mmHg at 25 o C, there was little compensation of extracellular pH after 24 h, P a CO 2 rose from 7.0 to 24.5 mmHg, and there were no changes in plasma strong ion concentrations. Compensation to a respiratory acidosis can be calculated as (Siesjo, 1971); the resultant percentage is the recovery of pH relative to its value at the increased P CO 2 if there were no change in []. For N. maculosus in the Stiffler et al (1983) study, compensation is 11%, low in comparison to similar calculations for Ambystoma tigrinum larvae (26–43%), and C. alleganiensis (40%) faced with a similar degree of environmental hypercarbia (Ultsch, 1996).…”

Section: Species Accountsmentioning

confidence: 99%

Metabolism, gas exchange, and acid‐base balance of giant salamanders

Ultsch

2011

Biological Reviews

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The giant salamanders are aquatic and paedomorphic urodeles including the genera Andrias and Cryptobranchus (Cryptobranchidae), Amphiuma (Amphiumidae), Siren (Sirenidae), and Necturus (Proteidae, of which only N. maculosus is considered 'a giant'). Species in the genera Cryptobranchus and Necturus are considered aquatic salamanders well adapted for breathing water, poorly adapted for breathing air, and with limited abilities to compensate acid-base disturbances. As such, they are water-breathing animals with a somewhat fish-like respiratory and acid-base physiology, whose habitat selection is limited to waters that do not typically become hypoxic or hypercarbic (although this assertion has been questioned for N. maculosus). Siren and Amphiuma species, by contrast, are dependent upon air-breathing, have excellent lungs, inefficient (Siren) or no (Amphiuma) gills, and are obligate air-breathers with an acid-base status more similar to that of terrestrial tetrapods. As such, they can be considered to be air-breathing animals that live in water. Their response to the aquatic hypercarbia that they often encounter is to maintain intracellular pH (pH(i) ) and abandon extracellular pH regulation, a process that has been referred to as preferential pH(i) regulation. The acid-base status of some present-day tropical air-breathing fishes, and of Siren and Amphiuma, suggests that the acid-base transition from a low PCO(2) -low [] system typical of water-breathing fishes to the high PCO(2) -high [] systems of terrestrial tetrapods may have been completed before emergence onto land, and likely occurred in habitats that were typically both hypoxic and hypercarbic.

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“…If ApH is taken from the initial maximal pH ehange, then one finds apparent buffer capacities to be much lower than if the restored pH^ is taken for calculation. Siesjo (1971) suggested that such a transient behaviour could be indicative of a time-dependent buffer capacity, arising from either contributions to the capacity from the added aeids themselves, or from metabolic adjustments triggered by the acid.…”

Section: Physicochemical Bufferingmentioning

confidence: 99%

Short‐term pH regulation in plants

Felle

1988

Physiologia Plantarum

102

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Cellular pH regulation consists of two features: (i) Long‐term pH homeostasis, which ensures that all H+ or OH− produced in excess is ultimately removed from the cell and which requires metabolic energy; (ii) short‐term reactions of the cell(s) to sudden shifts in intracellular pH, in order to prevent acute disturbances of metabolism. Recent progress in measuring and understanding of mainly short‐term cellular regulation is summarized, including cellular responses to pH loads that arise from different sources such as external pH, weak acids/bases, protonophores, metabolic inhibitors, H+/cotransport, light and phytohormones. Whereas the plasma membrane H+ pump and metabolic adjustments may serve both long‐ and short‐term pH control, physico‐chemical buffering and the translocation of H+ from and to cellular compartments render only time‐limited capacity for the neutralization of pH loads and seem exhausted within minutes. In spite of the widespread opinion that, because of tight regulation, intracellular pH does not vary with time, there is good evidence for long‐lasting pH changes in plant cells, i.e. after hormonal stimulation, light/dark changes or carboxylation during crassulacean acid metabolism (CAM). This emphasizes that cytoplasmic pH, besides being well regulated, is essential not only for the regulation of membrane transport but also as a cellular messenger.

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Quantification of pH Regulation in Hypercapnia and Hypocapnia

Cited by 40 publications

References 16 publications

Controlled Hyperventilation and Its Effect on Brain Energy and Acid‐Base Parameters

Controlled Hyperventilation and Its Effect on Brain Energy and Acid‐Base Parameters

Metabolism, gas exchange, and acid‐base balance of giant salamanders

Short‐term pH regulation in plants

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