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Titolo:
Apparent diffusion limitations for CO2 excretion in rainbow trout are relieved by injections of carbonic anhydrase
Autore:
Julio, AE; Desforges, PR; Perry, SF;
Indirizzi:
Univ Ottawa, Dept Biol, Ottawa, ON K1N 6N5, Canada Univ Ottawa Ottawa ON Canada K1N 6N5 ept Biol, Ottawa, ON K1N 6N5, Canada
Titolo Testata:
RESPIRATION PHYSIOLOGY
fascicolo: 1, volume: 121, anno: 2000,
pagine: 53 - 64
SICI:
0034-5687(200006)121:1<53:ADLFCE>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACID-BASE STATUS; SALMO-GAIRDNERI; ONCORHYNCHUS-MYKISS; GAS TRANSFER; DIOXIDE EXCRETION; OXYGEN-TRANSFER; BLOOD; FISH; GILLS; WATER;
Keywords:
carbon dioxide gill transfer; carbonic anhydrase; fish gill; diffusion limitation; fish, rainbow trout (Oncorhynchus mykiss); gas exchange, gill CO2 excretion; reaction, CO2-HCO3-;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Perry, SF Univ Ottawa, Dept Biol, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada Univ Ottawa 30 Marie Curie Ottawa ON Canada K1N 6N5 6N5, Canada
Citazione:
A.E. Julio et al., "Apparent diffusion limitations for CO2 excretion in rainbow trout are relieved by injections of carbonic anhydrase", RESP PHYSL, 121(1), 2000, pp. 53-64

Abstract

Experiments were performed in vivo to elucidate the underlying mechanism(s) of apparent diffusion limitations for CO2 excretion in rainbow trout (Oncorhynchus mykiss). Ligation of two gill arches and the associated expected reduction in gill surface area of 30% caused pronounced respiratory acidosis as indicated by elevated arterial blood P-CO2 (Pa-CO2) and reduced arterial blood pH. Under conditions of normoxia, arterial blood P-O2 (Pa-O2) was not significantly (statistically) reduced. However, during hypoxia (water P-O2 = 70-80 mmHg), the apparent trend for reduced Pa-O2 values became statistically significant in fish with 15% surface area reduction. To determine whether the elevated Pa-CO2 in fish with reduced surface area (30%) reflected true diffusion limitations or chemical equilibrium limitations imposed by the relatively slow rate of red blood cell Cl-/HCO3- exchange, fish were injected with carbonic anhydrase (CA) to permit catalysis of HCO3- dehydration within the plasma. Injection of CA caused a lowering of Pa-CO2 by 0.87 /- 0.32 mmHg within 120 min and thus essentially eliminated the increase in Pa-CO2 (1.04 +/- 0.33 mmHg) that was caused by the reduction in surface area. These results clearly demonstrate that the elevation in Pa-CO2 evoked by gill surface area reduction is a consequence of chemical equilibrium limitations rather than true diffusion limitations, per se. (C) 2000 Elsevier Science B.V. All rights reserved.

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Documento generato il 24/11/20 alle ore 22:42:11