scholarly journals A critical analysis of carbonic anhydrase function, respiratory gas exchange, and the acid-base control of secretion in the rectal gland of Squalus acanthias

2006 ◽  
Vol 209 (23) ◽  
pp. 4701-4716 ◽  
Author(s):  
T. J. Shuttleworth ◽  
J. Thompson ◽  
R. S. Munger ◽  
C. M. Wood
Keyword(s):  
Gas Exchange ◽  
Carbonic Anhydrase ◽  
Critical Analysis ◽  
Squalus Acanthias ◽  
Rectal Gland ◽  
Acid Base ◽  
Respiratory Gas Exchange

Control of rectal gland secretion by blood acid–base status in the intact dogfish shark (Squalus acanthias)

2007 ◽  
Vol 156 (2) ◽  
pp. 220-228 ◽  
Author(s):  
Chris M. Wood ◽  
R. Stephen Munger ◽  
Jill Thompson ◽  
Trevor J. Shuttleworth
Keyword(s):  
Squalus Acanthias ◽  
Gland Secretion ◽  
Rectal Gland ◽  
Acid Base ◽  
Acid Base Status ◽  
Dogfish Shark

Does gill boundary layer carbonic anhydrase contribute to carbon dioxide excretion: a comparison between dogfish (Squalus acanthias) and rainbow trout (Oncorhynchus mykiss)

1999 ◽  
Vol 202 (6) ◽  
pp. 749-756 ◽  
Author(s):  
S.F. Perry ◽  
K.M. Gilmour ◽  
N.J. Bernier ◽  
C.M. Wood
Keyword(s):  
Carbon Dioxide ◽  
Boundary Layer ◽  
Rainbow Trout ◽  
Carbonic Anhydrase ◽  
Carbonic Anhydrase Activity ◽  
Squalus Acanthias ◽  
Stopped Flow ◽  
Acid Base ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Co2 Excretion

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.

Effect of acetazolamide on respiratory gas exchange during hyperventilation in man

1962 ◽  
Vol 17 (1) ◽  
pp. 6-8 ◽  
Author(s):  
Johan H. Strömme ◽  
J. Fog
Keyword(s):  
Gas Exchange ◽  
Carbonic Anhydrase ◽  
Healthy Men ◽  
Respiratory Gas Exchange ◽  
The Mean ◽  
Significant Change

The effects of acetazolamide on the CO2 output and on the O2 uptake during hyperventilation have been investigated. Nine healthy men were given acetazolamide orally in doses of 10–12 mg/kg body wt. All showed a decrease in CO2 output during hyperventilation performed 2 hr after the dosage as compared to values obtained in tests without premedication. The mean reduction was about 12%. During these tests no significant change was recorded in the O2 uptake. The decreased output of CO2 is presumed to be caused by an inhibition by acetazolamide of the carbonic anhydrase present in the erythrocytes. Submitted on May 12, 1961

Respiratory Gas Exchange and Growth of Bonin Petrel Embryos

1982 ◽  
Vol 55 (2) ◽  
pp. 162-170 ◽  
Author(s):  
Ted N. Pettit ◽  
Gilbert S. Grant ◽  
G. Causey Whittow ◽  
Hermann Rahn ◽  
Charles V. Paganelli
Keyword(s):  
Gas Exchange ◽  
Respiratory Gas Exchange
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