Document Detail

Interaction of the autonomic nervous system with intrinsic cardiac rate regulation in the guinea-pig, Cavia porcellus.
MedLine Citation:
PMID:  11691608     Owner:  NLM     Status:  MEDLINE    
In the denervated mammalian heart a change in right atrial pressure will still alter heart rate (intrinsic rate response, IRR). We have examined the IRR in isolated right atria of the guinea-pig maintained in oxygenated Krebs-Henseleit solution at 37 degrees C, to compare with and extend studies in other species, and to determine whether the guinea-pig is a suitable model for electrophysiological studies of the IRR. Baseline diastolic transmural pressure was set at 2 mmHg. A 6-mmHg increase in right atrial pressure (RAP) caused an increase in atrial rate that reached a steady value of 15 min(-1) after 1-2 min. This response was enhanced by carbamylcholine and attenuated by isoprenaline. The influence of RAP on the rate response to vagal stimulation was examined. With RAP set at 8 mmHg, the reduction in atrial rate following vagal stimulation was 72+/-5% of that at 2 mmHg (n=6, mean+/-S.E., P<0.005). Continuous vagal stimulation produced a sustained bradycardia, and the effect of this bradycardia on the IRR was examined. When atrial rate was reduced 6% by vagal stimulation, the IRR was augmented to 202+/-21% of the control (n=6, P<0.005). This augmentation was larger (P<0.05) than that seen when atrial rate was reduced 8% by carbamylcholine (130+/-8% of control; n=7, P<0.05). Overall, the IRR in the guinea-pig is similar to that in the rabbit, and shows similar interactions with the autonomic nervous system.
S J Wilson; C P Bolter
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Comparative biochemistry and physiology. Part A, Molecular & integrative physiology     Volume:  130     ISSN:  1095-6433     ISO Abbreviation:  Comp. Biochem. Physiol., Part A Mol. Integr. Physiol.     Publication Date:  2001 Nov 
Date Detail:
Created Date:  2001-11-05     Completed Date:  2002-01-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9806096     Medline TA:  Comp Biochem Physiol A Mol Integr Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  723-30     Citation Subset:  IM    
Department of Physiology and the Centre for Neuroscience, School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
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MeSH Terms
Atrial Function
Autonomic Nervous System / metabolism*
Carbachol / pharmacology
Cardiotonic Agents / pharmacology
Guinea Pigs
Heart Atria / drug effects
Heart Rate*
Isoproterenol / pharmacology
Reg. No./Substance:
0/Cardiotonic Agents; 51-83-2/Carbachol; 7683-59-2/Isoproterenol

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

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