Document Detail

CO2 sensitivity of cat phrenic neurogram during hypoxic respiratory depression.
MedLine Citation:
PMID:  3139617     Owner:  NLM     Status:  MEDLINE    
The CO2 response of the phrenic neurogram before and during CO-induced isocapnic brain hypoxia was studied in peripherally chemodenervated, vagotomized, paralyzed, ventilated cats with blood pressure held constant. During inhalation of 0.5% CO in 40% O2, arterial O2 content (CaO2) was reduced to 40% and minute phrenic activity to 38.4 +/- 9.4% (SE; n = 9) of prehypoxic levels, primarily due to depression of peak phrenic amplitude (PP). CO2 response, defined as the slope of the plot of PP vs. end-tidal PCO2 during CO2 rebreathing, was unaffected by phrenic depression even to the point of total suppression of phrenic activity in two cats. The effect of the tissue metabolic acidosis associated with hypoxia on phrenic CO2 sensitivity was assessed in a separate group of cats by blocking lactate formation during hypoxia with dichloroacetate (DCA). Preventing lactic acidosis during hypoxia did not affect the CO2 response of the phrenic activity during hypoxia. We conclude that 1) hypoxic depression does not limit the ability of central respiratory neurons to respond to CO2, and 2) the failure of DCA to affect the CO2 response of the phrenic neurogram suggests that brain intracellular lactic acidosis does not modify the phrenic response to hypercapnia.
J E Melton; J A Neubauer; N H Edelman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  65     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1988 Aug 
Date Detail:
Created Date:  1988-11-22     Completed Date:  1988-11-22     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  736-43     Citation Subset:  IM    
Department of Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick 08903-0019.
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MeSH Terms
Anoxia / physiopathology*
Carbon Dioxide / pharmacology*
Dichloroacetic Acid / pharmacology
Lactates / metabolism
Lactic Acid
Phrenic Nerve / drug effects,  physiopathology*
Grant Support
Reg. No./Substance:
0/Lactates; 124-38-9/Carbon Dioxide; 50-21-5/Lactic Acid; 79-43-6/Dichloroacetic Acid

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