Document Detail


A new function for lactate in the toad Bufo marinus.
MedLine Citation:
PMID:  7928864     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In the amphibian Bufo marinus, progressive hypoxia below a critical PO2 elicits a transient 50% increase in O2 consumption that coincides with the onset of lactate formation. The present study was designed to test the hypothesis that lactate causes the observed rise in metabolic rate. Arterial bolus infusions of pH-neutral sodium lactate solutions (4 mmol/kg body wt) in toads maintained under hypoxia actually elicit a similar increase in metabolic rate. The application of adrenergic antagonists (bretylium tosylate, phentolamine, propranolol, and reserpine) inhibits this response, suggesting that catecholamines are involved. Moreover, animals injected with lactate move to a cooler environment (behavioral hypothermia), a behavioral response that is beneficial during hypoxia. We hypothesize that, in accordance with Cannon's concept of an emergency response, lactate may function as an alarm signal during hypoxia. However, the signal function of lactate is observed in animals both under hypoxia and under normoxia and should thus be considered in future studies whenever elevated lactate levels are present, e.g., during and after exercise.
Authors:
H O Pörtner; L G Branco; G M Malvin; S C Wood
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  76     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1994 Jun 
Date Detail:
Created Date:  1994-11-01     Completed Date:  1994-11-01     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2405-10     Citation Subset:  IM    
Affiliation:
Lovelace Institutes, Albuquerque, New Mexico 87108.
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MeSH Terms
Descriptor/Qualifier:
Alkalosis, Respiratory / blood,  physiopathology
Animals
Behavior, Animal / drug effects,  physiology
Body Temperature Regulation / drug effects,  physiology
Bufo marinus
Catecholamines / metabolism
Cold Temperature
Hydrogen-Ion Concentration
Lactates / blood*,  pharmacology
Lactic Acid
Oxygen Consumption / drug effects,  physiology
Saline Solution, Hypertonic
Sympathetic Nervous System / drug effects,  physiology
Grant Support
ID/Acronym/Agency:
HL-38942/HL/NHLBI NIH HHS; HL-40537/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Catecholamines; 0/Lactates; 0/Saline Solution, Hypertonic; 50-21-5/Lactic Acid

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


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