Document Detail

Control of rectal gland secretion by blood acid-base status in the intact dogfish shark (Squalus acanthias).
MedLine Citation:
PMID:  17049933     Owner:  NLM     Status:  MEDLINE    
In order to address the possible role of blood acid-base status in controlling the rectal gland, dogfish were fitted with indwelling arterial catheters for blood sampling and rectal gland catheters for secretion collection. In intact, unanaesthetized animals, isosmotic volume loading with 500 mmol L-1 NaCl at a rate of 15 mL kg-1 h-1 produced a brisk, stable rectal gland secretion flow of about 4 mL kg-1 h-1. Secretion composition (500 mmol L-1 Na+ and Cl-; 5 mmol L-1 K+; <1 mmol L-1 Ca2+, Mg2+, SO(4)2-, or phosphate) was almost identical to that of the infusate with a pH of about 7.2, HCO3- mmol L-1<1 mmol L-1 and a PCO2 (1 Torr) close to PaCO2. Experimental treatments superimposed on the infusion caused the expected disturbances in systemic acid-base status: respiratory acidosis by exposure to high environmental PCO2, metabolic acidosis by infusion of HCl, and metabolic alkalosis by infusion of NaHCO3. Secretion flow decreased markedly with acidosis and increased with alkalosis, in a linear relationship with extracellular pH. Secretion composition did not change, apart from alterations in its acid-base status, and made negligible contribution to overall acid-base balance. An adaptive control of rectal gland secretion by systemic acid-base status is postulated-stimulation by the "alkaline tide" accompanying the volume load of feeding and inhibition by the metabolic acidosis accompanying the volume contraction of exercise.
Chris M Wood; R Stephen Munger; Jill Thompson; Trevor J Shuttleworth
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-09-22
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  156     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2007 May 
Date Detail:
Created Date:  2007-03-05     Completed Date:  2007-05-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  220-8     Citation Subset:  IM    
Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario, Canada L8S 4K1.
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MeSH Terms
Acid-Base Equilibrium / physiology*
Acidosis, Respiratory / blood*
Alkalosis, Respiratory / blood
Dogfish / physiology*
Salt Gland / physiology*,  secretion
Water-Electrolyte Balance / physiology*

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

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