AJP - Heart and Circulatory Physiology, Vol 251, Issue 4 764-H773, Copyright © 1986 by American Physiological Society

ARTICLES

Selective vagal innervation of sinoatrial and atrioventricular nodes in canine heart

J. L. Ardell and W. C. Randall

Parasympathetic pathways mediating chronotropic and dromotropic responses to cervical vagal stimulation were determined from sequential, restricted, intrapericardial dissection around major cardiac vessels. Although right cervical vagal input evoked significantly greater bradycardia, supramaximal electrical stimulation of either vagus produced similar ventricular rates, both with and without simultaneous atrial pacing. Dissection of the triangular fat pad at the junction of the inferior vena cava-inferior left atrium (IVC-ILA) invariably eliminated all vagal input to the atrioventricular (AV) nodal region. Yet IVC-ILA dissection had minimal influence on evoked-chronotropic responses to either cervical vagal or stellate ganglia stimulation. Respective intrapericardial projection pathways, from either right or left vagi, are sufficiently distinct to allow unilateral parasympathetic denervation of the sinoatrial (SA) and atrioventricular (AV) nodal regions. Left vagal projections to the SA and AV nodal regions course primarily along and between the right pulmonary artery and left superior pulmonary vein. Right vagal projections to the SA and AV nodal regions are somewhat more diffuse but concentrate around the right pulmonary vein complex and adjacent segments of the right pulmonary artery. We conclude there are parallel, yet functionally distinct, inputs from right and left vagi to the SA and AV nodal regions.

This article has been cited by other articles:

				J. A. Armour Potential clinical relevance of the 'little brain' on the mammalian heart Exp Physiol, February 1, 2008; 93(2): 165 - 176. [Abstract] [Full Text] [PDF]

				M. Waldmann, G. W. Thompson, G. C. Kember, J. L. Ardell, and J. A. Armour Stochastic behavior of atrial and ventricular intrinsic cardiac neurons J Appl Physiol, August 1, 2006; 101(2): 413 - 419. [Abstract] [Full Text] [PDF]

				A. L. Gray, T. A. Johnson, J. L. Ardell, and V. J. Massari Parasympathetic control of the heart. II. A novel interganglionic intrinsic cardiac circuit mediates neural control of heart rate J Appl Physiol, June 1, 2004; 96(6): 2273 - 2278. [Abstract] [Full Text] [PDF]

				A. L. Gray, T. A. Johnson, J.-M. Lauenstein, S. S. Newton, J. L. Ardell, and V. J. Massari Parasympathetic control of the heart. III. Neuropeptide Y-immunoreactive nerve terminals synapse on three populations of negative chronotropic vagal preganglionic neurons J Appl Physiol, June 1, 2004; 96(6): 2279 - 2287. [Abstract] [Full Text] [PDF]

				D. C. Randall, D. R. Brown, A. S. McGuirt, G. W. Thompson, J. A. Armour, and J. L. Ardell Interactions within the intrinsic cardiac nervous system contribute to chronotropic regulation Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2003; 285(5): R1066 - R1075. [Abstract] [Full Text] [PDF]

				R. C. Arora, R. Cardinal, F. M. Smith, J. L. Ardell, L. J. Dell'Italia, and J. A. Armour Intrinsic cardiac nervous system in tachycardia induced heart failure Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2003; 285(5): R1212 - R1223. [Abstract] [Full Text] [PDF]