Document Detail

CO2 back-diffusion in the rete aids O2 secretion in the swimbladder of the eel.
MedLine Citation:
PMID:  2113304     Owner:  NLM     Status:  MEDLINE    
In order to estimate the relative importance of back-diffusion of O2 and CO2 for their partial pressure enhancement in the swimbladder, we have determined O2 and CO2 partial pressure and content and pH in microsamples collected non-obstructively from the afferent and efferent rete vessels in the European eel. 1. The PO2 increased significantly along the arterial vessels of the rete (from 33 to 303 Torr), with no change in O2 content, suggesting O2 not to be exchanged in the rete counter-current system. 2. A corresponding increase of PCO2 (from 4 to 35 Torr) was accompanied by a significant rise in CO2 content (from 8 to 15 mmol.L-1), suggesting significant CO2 back-diffusion in the rete. 3. Changes in PO2 during passage of blood through the swimbladder epithelium were variable and small, and the PO2 in rete venous blood was similar to that in rete arterial blood, explaining the lack of O2 back-diffusion. 4. Using blood CO2 dissociation data, about 70% of the rise in arterial CO2 content was estimated to derive from diffusion of CO2, the remaining 30% from diffusion of HCO3-, from venous to arterial rete capillaries, or from H+ transport in the opposite direction. The data indicate that CO2 back-diffusion in the rete does not only raise the rete arterial PCO2; it also reduces the O2 capacity (Root effect) and thus enhances the arterial PO2.
H Kobayashi; B Pelster; P Scheid
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Respiration physiology     Volume:  79     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  1990 Mar 
Date Detail:
Created Date:  1990-07-25     Completed Date:  1990-07-25     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  231-42     Citation Subset:  IM    
Institut für Physiologie, Ruhr-Universität Bochum, F.R.G.
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MeSH Terms
Air Sacs / blood supply,  metabolism*
Biological Transport / physiology
Blood Gas Analysis
Carbon Dioxide / blood,  metabolism*,  pharmacokinetics
Eels / metabolism*
Hydrogen-Ion Concentration
Oxygen / blood,  metabolism*
Partial Pressure
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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