Document Detail

Hypoxic cardiorespiratory reflexes in the facultative air-breathing fish jeju (Hoplerythrinus unitaeniatus): role of branchial O2 chemoreceptors.
MedLine Citation:
PMID:  20221608     Owner:  NLM     Status:  MEDLINE    
In one series of experiments, heart frequency (f (H)), blood pressure (P (a)), gill ventilation frequency (f ( R )), ventilation amplitude (V (AMP)) and total gill ventilation (V (TOT)) were measured in intact jeju (Hoplerythrinus unitaeniatus) and jeju with progressive denervation of the branchial branches of cranial nerves IX (glossopharyngeal) and X (vagus) without access to air. When these fish were submitted to graded hypoxia (water PO(2) approximately 140, normoxia to 17 mmHg, severe hypoxia), they increased f ( R ), V (AMP), V (TOT) and P (a) and decreased f (H). In a second series of experiments, air-breathing frequency (f (RA)), measured in fish with access to the surface, increased with graded hypoxia. In both series, bilateral denervation of all gill arches eliminated the responses to graded hypoxia. Based on the effects of internal (caudal vein, 150 microg NaCN in 0.2 mL saline) and external (buccal) injections of NaCN (500 microg NaCN in 1.0 mL water) on f (R), V (AMP), V (TOT), P (a) and f (H) we conclude that the O(2) receptors involved in eliciting changes in gill ventilation and associated cardiovascular responses are present on all gill arches and monitor the O(2) levels of both inspired water and blood perfusing the gills. We also conclude that air breathing arises solely from stimulation of branchial chemoreceptors and support the hypothesis that internal hypoxaemia is the primary drive to air breathing.
Jane Mello Lopes; Cheila de Lima Boijink; Luiz Henrique Florindo; Cleo Alcantara Costa Leite; Ana Lúcia Kalinin; William K Milsom; Francisco Tadeu Rantin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-03-11
Journal Detail:
Title:  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology     Volume:  180     ISSN:  1432-136X     ISO Abbreviation:  J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-14     Completed Date:  2010-10-28     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8413200     Medline TA:  J Comp Physiol B     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  797-811     Citation Subset:  IM    
Department of Physiological Sciences, Federal University of São Carlos, Via Washington Luiz, km 235, São Carlos, SP, 13565-905, Brazil.
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MeSH Terms
Anoxia / physiopathology*
Blood Pressure / drug effects,  physiology
Chemoreceptor Cells / physiology*
Cranial Nerves / surgery
Fishes / physiology*
Gills / cytology,  physiology*
Heart Rate / drug effects,  physiology*
Oxygen Consumption / physiology*
Reflex / physiology
Respiratory Mechanics / drug effects,  physiology*
Sodium Cyanide / pharmacology
Tachycardia / physiopathology
Time Factors
Reg. No./Substance:
143-33-9/Sodium Cyanide

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