Document Detail


Branchial and systemic roles of adenosine receptors in rainbow trout: an in vivo microscopy study.
MedLine Citation:
PMID:  8853389     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purinergic branchial vasomotor control in rainbow trout (Oncorhynchus mykiss) was studied using an epi-illumination microscope equipped with a water-immersion objective. Cardiac output (Q), heart rate, and dorsal (PDA) and ventral (PVA) aortic pressures were recorded simultaneously. Prebranchial injection of adenosine or the A1-receptor agonist N6-cyclopentyl-adenosine (CPA) constricted the distal portion of the filament vasculature, which coincided with an increase of PVA. The A2-receptor agonist PD-125944 was without effect. After adenosine and CPA injection, an overflow of blood to the secondary system was repeatedly observed unless blood flow came to a complete stop. The lack of a concomitant reduction of Q suggested a redistribution of blood to the secondary system and to more proximal parts of the filament. The branchial effects of adenosine and CPA were completely blocked by the unspecific adenosine receptor antagonist amino-phylline and the specific A1-receptor antagonist N6-cyclopen-tyltheophylline. The results suggest that A1-receptors alone mediate the branchial vasoconstriction observed. Thus the responses of the branchial vasculature to adenosine include a vasoconstriction of the filament vasculature mediated via specific A1 receptors and a redistribution of blood flow to the secondary system and to proximal parts of the filament. Additional cardiovascular effects of adenosine included decreased systemic vascular resistance and heart rate.
Authors:
L Sundin; G E Nilsson
Related Documents :
7830329 - Coronary blood flow autoregulation and flow heterogeneity in the stunned heart.
3775769 - Coronary dilator effect of mci-176, a new calcium channel blocker, in dogs.
9006289 - Determination of coronary flow measurements by transesophageal echocardiography: depend...
15163939 - Effects of coil closure of patent ductus arteriosus on left anterior descending coronar...
872309 - The extraction of thallium-201 by the myocardium.
7273359 - Evidence against significant resting sympathetic coronary vasoconstrictor tone in the c...
8123389 - Magnetic resonance imaging of extradural blood patches: appearances from 30 min to 18 h.
6259889 - Transient intestinal ischaemia induced by degradable starch microspheres. experiments i...
8950589 - Isovolemic hemodilution increases retinal tissue oxygen tension.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  271     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1996 Sep 
Date Detail:
Created Date:  1996-12-05     Completed Date:  1996-12-05     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R661-9     Citation Subset:  IM    
Affiliation:
Department of Zoophysiology, University of Göteborg. L. Sundin@zool.gu.se
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adenosine / analogs & derivatives,  pharmacology
Animals
Blood Circulation / drug effects,  physiology*
Branchial Region / blood supply,  drug effects,  physiology*
Female
Male
Oncorhynchus mykiss / physiology*
Receptors, Purinergic P1 / physiology*
Theophylline / analogs & derivatives
Vasoconstriction
Vasodilator Agents / pharmacology
Chemical
Reg. No./Substance:
0/Receptors, Purinergic P1; 0/Vasodilator Agents; 41552-82-3/N(6)-cyclopentyladenosine; 58-55-9/Theophylline; 58-61-7/Adenosine

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


Previous Document:  Conscious obese rats have impaired reflex bradycardia and enhanced norepinephrine sensitivity.
Next Document:  In vivo increase of the human lens equatorial diameter during accommodation.