Journal of Applied Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 70: 1175-1183, 1991;
8750-7587/91 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ardell, J. L.
Right arrow Articles by Kim, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ardell, J. L.
Right arrow Articles by Kim, T.

Journal of Applied Physiology, Vol 70, Issue 3 1175-1183, Copyright © 1991 by American Physiological Society

ARTICLES

Autonomic regulation of subsidiary atrial pacemakers during exercise

J. L. Ardell, W. C. Randall, G. Pomeroy, M. Lawton and T. Kim
Department of Physiology, University of South Alabama, Mobile 36688.

Cardiac responses to graded treadmill exercise were compared in conscious dogs before and after excision of the sinoatrial node (SAN) and adjacent tissue along the sulcus terminalis. The chronotropic and dromotropic responses to dynamic exercise were compared with and without selective muscarinic (atropine) and/or beta-adrenergic (timolol) blockade. With the SAN intact, cardiac acceleration was prompt during onset of exercise and in proportion to work intensity. Immediately after SAN excision (1-7 days), pacemaker activity exhibited marked instability in rate and pacemaker location, with rapid shifts between atrial and junctional foci. Soon thereafter (1-2 wk), subsidiary atrial pacemakers (SAPs) assumed the primary pacemaker function. Although the SAP foci demonstrated stable heart rates and atrioventricular (AV) intervals at rest and during exercise, heart rates at rest and during steady-state exercise were reduced 34% from corresponding levels in the SAN-intact state, both with and without selective autonomic blockade. For control of dromotropic function, animals with SAP foci showed pronounced shortening in AV interval in conjunction with exercise that was further exacerbated by pretreatment with atropine. Eight weeks after excision of the primary SAN pacemakers, direct electrophysiological mapping localized the SAP foci to either the inferior right atrium along the sulcus terminalis or the dorsal cranial right atrium (in or near Bachmann's bundle). Animals with SAPs localized to the inferior right atrium had a more marked suppression in heart rate with a corresponding greater decrease in AV interval during exercise than dogs with SAP foci identified within the dorsal cranial right atrium.


This article has been cited by other articles:


Home page
 J. Pharmacol. Exp. Ther.Home page
Y. Furukawa, Y. Miyashita, K. Nakajima, M. Hirose, F. Kurogouchi, and S. Chiba
Effects of Verapamil, Zatebradine, and E-4031 on the Pacemaker Location and Rate in Response to Sympathetic Stimulation in Dog Hearts
J. Pharmacol. Exp. Ther., June 1, 1999; 289(3): 1334 - 1342.
[Abstract] [Full Text]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online