Donate Help Contact The AHA Sign In Home
American Heart Association
Circulation Research
Search: search_blue_button Advanced Search
« Previous Article | Table of Contents | Next Article »
Circulation Research. 1979;44:112-120

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
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
Right arrowRequest Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Prystowsky, E. N.
Right arrow Articles by Strauss, H. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Prystowsky, E. N.
Right arrow Articles by Strauss, H. C.

Circulation Research, Vol 44, 112-120, Copyright © 1979 by American Heart Association

ARTICLES

An analysis of the effects of acetylcholine on conduction and refractoriness in the rabbit sinus node

EN Prystowsky, AO Grant, AG Wallace and HC Strauss

The effects of acetylcholine (ACh) on sinus node automaticity, atrio- sinus conduction, and refractoriness were studied in 41 isolated rabbit right atrial preparations. Average control rate was 126 beats/min, and ACh 5 x 10(-8) M, 5 x 10(-7) M, and 5 x 10(-6) M significantly decreased heart rate by 7, 15, and 43%, respectively (P less than 0.01, 0.001, and 0.001). Atrio-sinus conduction time at a pacing cycle length of 400 msec did not significantly change during exposure to ACh 5 x 10(- 8) and 5 x 10(-7) M. However, the mean effective refractory period (ERP) of the sinus node, at a pacing cycle length of 400 msec, increased from 183 +/- 16 msec to 210 +/- 24 msec during exposure to ACh 5 x 10(-7) M (P less than 0.025). The change in ERP followed the change in action potential duration. In contrast to the lack of effect of ACh 5 x 10(-7) M on atrio-sinus conduction time, ACh 5 x 10(-6) M caused 2:1 atrio-sinus block in 8 of 10 experiments. The site of block was identified using multiple microelectrode impalements, and occurred between the perinodal fibers bordering on the edge of the sinus node and the pacemaker area in the sinus node proper. When the pacing cycle length was increased and 1:1 atrio-sinus conduciton was present, conduction time did not significantly differ from control. At this longer pacing cycle length the mean ERP of the sinus node was 380 msec greater than control and lasted well after repolarization was completed. Thus, atrio-sinus block during exposure to ACh 5 x 10(-6) M resulted from a marked prolongation of refractoriness.


This article has been cited by other articles:


Home page
 Physiol. Rev.Home page
M. Biel, C. Wahl-Schott, S. Michalakis, and X. Zong
Hyperpolarization-Activated Cation Channels: From Genes to Function
Physiol Rev, July 1, 2009; 89(3): 847 - 885.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
H. L. Lujan, Y. Chen, and S. E. DiCarlo
Paraplegia increased cardiac NGF content, sympathetic tonus, and the susceptibility to ischemia-induced ventricular tachycardia in conscious rats
Am J Physiol Heart Circ Physiol, May 1, 2009; 296(5): H1364 - H1372.
[Abstract] [Full Text] [PDF]

Home page
 CirculationHome page
C.-W. Chiou, J. N. Eble, and D. P. Zipes
Efferent Vagal Innervation of the Canine Atria and Sinus and Atrioventricular Nodes: The Third Fat Pad
Circulation, June 3, 1997; 95(11): 2573 - 2584.
[Abstract] [Full Text]


Circulation Research Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search
Copyright © 1979 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited.