Selective Hypervagotonia Isolated to the Atrioventricular Node

Rubin, David A.; Nieminski, Karen E.; Woolf, Paul K.; Herman, Michael V.

doi:10.1111/j.1540-8159.1988.tb06269.x

Cited by 3 publications

(1 citation statement)

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“…It also allows parallel setting and/or recording of cardiovascular parameters to be made in conjunction with functional studies on central control of reflex cardiovascular function. Such studies are necessary to determine the role of parallel effector pathways to the heart, and to determine whether selective activation or ablation of discrete ganglionic sites may be an advantageous approach in the therapy of vagally dependent cardiac arrhythmias (Rubin et al 1988;Schauerte et al 2000).…”

Section: Figurementioning

confidence: 99%

Differential Chronotropic and Dromotropic Responses to Focal Stimulation of Cardiac Vagal Ganglia in the Rat

Sampaio

Mauad

Spyer

et al. 2003

Experimental Physiology

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Activity in vagal preganglionic motoneurones running to the heart provokes a generalized cardioinhibition producing a decrease not only in heart rate (chronotropy), but also in the rate of atrioventricular (AV) conduction (dromotropy), and in the force of myocardial contraction (inotropy). These effects are secondary to, and are contingent upon, excitation of ganglion cells located in clusters on the epicardium of the dorsum of the atria, closely apposed to the sites of entry of the major veins. There is evidence that in many of the larger mammalian species, the ganglion cells are clustered into discrete zones or 'fat pads' which project to different regions of the heart and selectively control cardiac function (Ardell & Randall, 1986; Randall et al. 1986a,b;Gatti et al. 1995Gatti et al. , 1997. Several recent studies have described the anatomy of the cardiac vagal ganglia in the rat (Pardini et al. 1987;Abrahamian et al. 1991;Klimaschewski et al. 1992;Burkholder et al. 1992;deSouza et al. 1996;Cheng et al. 1999;Cheng & Powley, 2000).Although the results of some of these studies suggest the existence of a functional topography (e.g. Pardini et al. 1987), there is little clear physiological or pharmacological evidence of this in the rat. In the only previous study of a possible functional organization of rat cardiac ganglia (Burkholder et al. 1992), a brief description is given of a partial selectivity revealed by differing responses to vagal stimulation following local infiltration of hexamethonium into identified fat pads.Data from preliminary experiments in this laboratory suggest that glutamate excitation of cardiac vagal preganglionic motoneurones from different regions of the rat nucleus ambiguus results in differential chronotropic and dromotropic effects (Sampaio et al. 2000). That this may result from a different termination pattern of preganglionic axons onto ganglion cells from different ganglionic clusters is supported by the finding of restricted ganglionic innervation from motoneurones labelled with anterograde Vagal cardioinhibition is exerted through a reduction not only in the heart rate but also in the rate of propagation of the cardiac action potential and in myocardial contractility. In several species, such effects can be produced independently by selective activation of ganglia in identified 'fat pads'. In this study we investigate differential control of heart rate and atrioventricular conduction by two ganglionic clusters in the rat, a species increasingly important in studies of cardiovascular control. Epicardial sites producing low-threshold changes in P-P and P-R interval of the ECG in an arterially perfused preparation were explored with concentric bipolar stimulating electrodes. Stimulation sites centred on two principal ganglia, the sinoatrial (SA) ganglion at the junction of the right superior vena cava and right atrium, and the atrioventricular (AV) ganglion at the junction of the inferior pulmonary veins and left atrium. Stimulation of the SA ganglion decreased heart rate in all ...

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Section: Figurementioning

confidence: 99%