Document Detail

Alpha2 adrenergic receptors and the central control of breathing in the cane toad, Bufo marinus.
MedLine Citation:
PMID:  11282388     Owner:  NLM     Status:  MEDLINE    
The effect of adrenergic agents on the central control of breathing in the cane toad, Bufo marinus, was tested by applying adrenergic agents to the ventral medullary surface of decerebrate adult toads. Toads were unidirectionally ventilated while recording lung, buccal, and artery blood pressures (BPI), as well as heart rate (HR). Following a control period, filter paper pledgets soaked in the appropriate solution (epinephrine - 0.023, 0.05, 0.10, and 0.23 mM; norepinephrine - 0.002, 0.016, 0.032, and 0.16 mM; clonidine - 0.00375, 0.0375, and 0.375 mM; or yohimbine - 0.43) mM) were placed bilaterally on the ventral medullary surface. Epinephrine significantly increased the number of breaths (26%), lung amplitude (9%), and episode duration (21%), but had no effect on BP or HR. The alpha2-agonist. clonidine, significantly increased respiratory activity at moderate doses (0.0375 mM) and decreased activity at high doses (0.375 mM), however, it failed to elicit significant changes in BP or HR. Pretreatment with the alpha2-adrenoceptor antagonist, yohimbine (0.43 mM), blocked the clonidine induced changes in respiratory activity. Yohimbine had no effect on cardiorespiratory parameters. Norepinephrine had no effect on either cardiovascular or respiratory variables. Thus, it appears that an alpha2 adrenergic mechanism is involved in the central control of respiration in this lower vertebrate.
J E Rives; D G Bernard
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Respiration physiology     Volume:  125     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  2001 Apr 
Date Detail:
Created Date:  2001-04-03     Completed Date:  2001-06-28     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  213-23     Citation Subset:  IM    
Department of Biology, University of Texas at Arlington, 501 Nedderman Drive, Box 19498, Arlington, TX 76019, USA.
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MeSH Terms
Adrenergic alpha-Agonists / pharmacology
Adrenergic alpha-Antagonists / pharmacology
Blood Pressure / drug effects,  physiology
Bufo marinus / physiology*
Clonidine / pharmacology
Decerebrate State / physiopathology
Epinephrine / pharmacology
Medulla Oblongata / drug effects,  physiology
Norepinephrine / pharmacology
Receptors, Adrenergic, alpha-2 / physiology*
Respiratory Mechanics / drug effects,  physiology*
Yohimbine / pharmacology
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Adrenergic alpha-Antagonists; 0/Receptors, Adrenergic, alpha-2; 146-48-5/Yohimbine; 4205-90-7/Clonidine; 51-41-2/Norepinephrine; 51-43-4/Epinephrine

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

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