scholarly journals Carbon dioxide elimination by cardiomyocytes: a tale of high carbonic anhydrase activity and membrane permeability

2017 ◽  
Vol 221 (2) ◽  
pp. 95-97
Author(s):  
E. R. Swenson
PEDIATRICS ◽  
1968 ◽  
Vol 42 (3) ◽  
pp. 429-436
Author(s):  
E. Poblete ◽  
D. W. Thibeault ◽  
P. A. M. Auld

Carbonic anhydrase activity was measured in the blood of premature and full-term infants to determine if the arterial-alveolar carbon dioxide gradient was related to low levels of carbonic anhydrase. The time at which levels in these infants approached the adult was studied as well. The study demonstrates that CO2 gradients do not correlate with blood carbonic anhydrase activity, and minimal or no activity can be associated with a small gradient. An increase in the carbonic anhydrase activity-produced by transfusion did not significantly change the CO2 gradient. Premature infants approach adult levels of activity in 6 to 7 months.


1959 ◽  
Vol 14 (1) ◽  
pp. 109-115 ◽  
Author(s):  
John C. Mithoefer

The effect of carbonic anhydrase inhibition on carbon dioxide elimination by the lungs has been studied in dogs by the following four experimental approaches: 1) the alveolar pathway (PaOO2 and PaCOCO2) was measured during the hyperventilation which follows carbonic anhydrase inhibition and compared to the normal pathway at the same hyperventilation. 2) The alveolar gas tensions were measured following carbonic anhydrase inhibition when the ventilation was held constant. 3) The changes in PaCOCO2 were measured when the ventilation was suddenly, artificially changed to a new level in the presence of carbonic anhydrase inhibition and in normal animals. 4) The CO2 output was measured directly during the hyperventilation which results from carbonic anhydrase inhibition, during the same hyperventilation in the normal animal and following carbonic anhydrase inhibition when the ventilation is held constant. These experiments demonstrate an immediate fall in CO2 output relative to the ventilation when carbonic anhydrase is inhibited, resulting in CO2 retention until a new steady state has been reached. An hypothesis is presented to explain the effect of carbonic anhydrase inhibition on CO2 transport. Submitted on March 28, 1958


2020 ◽  
Author(s):  
Sam P. Jones ◽  
Aurore Kaisermann ◽  
Jerome Ogee ◽  
Steven Wohl ◽  
Alexander W. Cheesman ◽  
...  

Abstract. The oxygen isotope composition (δ18O) of atmospheric carbon dioxide (CO2) can be used to estimate gross primary production at the ecosystem-scale and above. Understanding how and why the rate of oxygen isotope exchange between soil water and CO2 (kiso) varies can help to reduce uncertainty in the retrieval of such estimates. The expression and activity of carbonic anhydrases in soils are important drivers of variations in kiso. Here we estimate kiso and measure associated soil properties in laboratory incubation experiments using 44 soils sampled from sites across western Eurasia and northeastern Australia. Observed kiso exceeded theoretical uncatalysed rates indicating the significant influence of carbonic anhydrases on the variability observed among the soils studied. We identify soil pH as the principal source of variation, with greater kiso under alkaline conditions suggesting that shifts in microbial community composition or intra-extra cellular dissolved inorganic carbon gradients induce the expression of more or higher activity forms of carbonic anhydrases. We also show for the first time in soils that the presence of nitrate under acidic conditions reduces kiso, potentially reflecting the direct or indirect inhibition of carbonic anhydrases. This effect was confirmed by a supplementary ammonium nitrate fertilisation experiment conducted on a subset of the soils. Future changes in atmospheric nitrogen deposition or land-use may thus influence carbonic anhydrase activity. Greater microbial biomass also increased kiso under a given set of chemical conditions likely highlighting the ubiquity of carbonic anhydrase expression by soil microbial communities. These data provide the most extensive analysis of spatial variations in soil kiso to date and indicate key controls required to predict variations in kiso at the scales needed to improve efforts to constrain gross primary productivity using the δ18O of atmospheric CO2.


1999 ◽  
Vol 202 (6) ◽  
pp. 749-756 ◽  
Author(s):  
S.F. Perry ◽  
K.M. Gilmour ◽  
N.J. Bernier ◽  
C.M. Wood

In vivo experiments were conducted on spiny dogfish (Squalus acanthias) and rainbow trout (Oncorhynchus mykiss) in sea water to determine the potential role of externally oriented or gill boundary layer carbonic anhydrase in carbon dioxide excretion. This was accomplished by assessing pH changes in expired water using a stopped-flow apparatus. In dogfish, expired water was in acid-base disequilibrium as indicated by a pronounced acidification (delta pH=−0.11+/−0.01; N=22; mean +/− s.e.m.) during the period of stopped flow; inspired water, however, was in acid-base equilibrium (delta pH=−0.002+/−0.01; N=22). The acid-base disequilibrium in expired water was abolished (delta pH=−0.005+/−0.01; N=6) by the addition of bovine carbonic anhydrase (5 mg l-1) to the external medium. Addition of the carbonic anhydrase inhibitor acetazolamide (1 mmol l-1) to the water significantly reduced the magnitude of the pH disequilibrium (from −0.133+/−0.03 to −0.063+/−0.02; N=4). However, after correcting for the increased buffering capacity of the water caused by acetazolamide, the acid-base disequilibrium during stopped flow was unaffected by this treatment (control delta [H+]=99.8+/−22.8 micromol l-1; acetazolamide delta [H+]=81.3+/−21.5 micromol l-1). In rainbow trout, expired water displayed an acid-base disequilibrium (delta pH=0.09+/−0.01; N=6) that also was abolished by the application of external carbonic anhydrase (delta pH=0.02+/−0.01).The origin of the expired water acid-base disequilibrium was investigated further in dogfish. Intravascular injection of acetazolamide (40 mg kg-1) to inhibit internal carbonic anhydrase activity non-specifically and thus CO2 excretion significantly diminished the extent of the expired water disequilibrium pH after 30 min (from −0.123+/−0.01 to −0.065+/−0.01; N=6). Selective inhibition of extracellular carbonic anhydrase activity using a low intravascular dose (1.3 mg kg-1) of the inhibitor benzolamide caused a significant reduction in the acid-base disequilibrium after 5 min (from −0.11+/−0.01 to −0.07+/−0. 01; N=14). These results demonstrate that the expired water acid-base disequilibrium originates, at least in part, from excretory CO2 and that extracellular carbonic anhydrase in dogfish may have a significant role in carbon dioxide excretion. However, externally oriented carbonic anhydrase (if present in dogfish) plays no role in catalysing the hydration of the excretory CO2 in water flowing over the gills and thus is unlikely to facilitate CO2 excretion.


Planta ◽  
1995 ◽  
Vol 196 (4) ◽  
Author(s):  
Gilles Peltier ◽  
Laurent Cournac ◽  
Val�rie Despax ◽  
Bernard Dimon ◽  
Laurent Fina ◽  
...  

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