Activity of single efferent fibres in the cervical vagus nerve of the dog, with special reference to possible cardio‐inhibitory fibres

Jewett, Don L.

doi:10.1113/jphysiol.1964.sp007520

Cited by 191 publications

(117 citation statements)

References 44 publications

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“…However, AV nodal conduction curves in these patients also remained unchanged. This is consistent with a disparate effect on the SA and AV node, which is known to exist in response to fluctuations in baroreflexmediated vagal tone in animals 7 and humans. 6 In all cases in which ventriculophasic AV nodal conduction was seen, it was noted on the steep portion of the AV nodal conduction curve and increased in an absolute amount as the paced atrial rate was increased until Wenckebach occurred.…”

Section: Previous Human Studiessupporting

confidence: 63%

“…In these studies, brief burst stimulation of the vagal efferent were meant to simulate those caused by stimulation of the baroreflex in response to beat-to-beat fluctuations in arterial pressure. 7,8 Burst vagal stimulation was found to cause sinus node slowing in a phase-dependent manner. 9 -11 At the level of the AV node, most studies found that dromotropic effects were balanced by effects on the sinus node so that 1:1 conduction was maintained over a wide spectrum of stimulation frequencies.…”

Section: Previous Animal Studiesmentioning

confidence: 99%

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Ventriculophasic Modulation of Atrioventricular Nodal Conduction in Humans

Skanes

Tang

1998

Circulation

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Background-Baroreceptor-mediated phasic changes in vagal tone have been hypothesized to cause ventriculophasic sinus arrhythmia (VPSA). The objectives of this study were to demonstrate ventriculophasic modulation of AV nodal conduction and to substantiate the role of the baroreflex on ventriculophasic AV nodal conduction (VPAVN) by pharmacological perturbation of parasympathetic tone. Methods and Results-Twelve patients with infra-Hisian second-degree heart block and VPSA were studied. Incremental atrial pacing was performed until AV nodal Wenckebach block at baseline, after phenylephrine infusion, and after atropine. AV nodal conduction curves were constructed for each phase and compared. At baseline, VPAVN was present in 9 of 12 patients on the steep portion of the AV nodal conduction curves. Phenylephrine increased systolic blood pressure from 149Ϯ33 to 177Ϯ22 mm Hg (PϽ0.001) and sinus cycle length from 844Ϯ169 to 1010Ϯ190 ms (PϽ0.001) and shifted the AV nodal conduction curves up and to the right. Phenylephrine induced VPAVN in 2 of 3 patients in whom it was not present at baseline and in 11 of 12 total. Atropine abolished both VPSA and VPAVN in all patients. Conclusions-VPAVN was demonstrated in patients with infra-Hisian second-degree AV block. It was accentuated by phenylephrine and abolished by atropine, suggesting a baroreflex mechanism for VPSA and VPAVN. (Circulation. 1998;97:2245-2251.)

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Section: Previous Human Studiessupporting

confidence: 63%

Section: Previous Animal Studiesmentioning

confidence: 99%

Ventriculophasic Modulation of Atrioventricular Nodal Conduction in Humans

Skanes

Tang

1998

Circulation

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“…since, as Holmes (1954) and Jewett (1964) have demonstrated, the existence of an afferent discharge arising from the carotid sinus may be recorded in fibres dissected from the central end of a cut aortic nerve. This phenomenon has been attributed to a bifurcation of the afferent fibre at some point central to the recording site; a situation comparable to that described for frog tactile receptors by Adrian et al (1931).…”

mentioning

confidence: 99%

An electrophysiological study of single vagal efferent units associated with gastric movements in sheep

Iggo¹,

Leek²

1967

The Journal of Physiology

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SUMMARY1. A method for obtaining reticulo-ruminal movements for up to 19 hr in halothane-anaesthetized sheep is described. The duration, wave form and frequency of the movements resembles those in the conscious animal except that ruminal movements have a lower amplitude.2. A method of recording for up to 51 hr single efferent unit discharges from fibres presumed to innervate the reticulo-rumen is described.3. At least seven distinguishable types of discharge pattern were recorded. By relating these temporally to movements of the reticulum and rumen it was concluded that Types I, II and III occurred in fibres innervating the reticulum or associated structures, Type IV the rumen and Types V, VI and VII other gastric structures not yet identified. Apart from Type VII units there was no 'resting discharge' in efferent fibres during the quiescent phase of the gastric cycle.4. We conclude that the co-ordination of the complex sequence of gastric movements in ruminant animals is a function of the 'gastric centres' in the hind-brain through their ability to determine the pattern, durations, spike frequencies and temporal interrelationships of discharges in gastric motoneurons innervating the different parts of the forestomach.

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“…Kirchheim, 1976), produced changes in the predicted direction for cardiac vagus fibres and has previously been used in the definition of such efferent vagus nerve fibres (e.g. Jewett, 1964;Neil, 1979). In a previous study, it was shown that all the responsive efferent vagus nerve fibres also responded to stimulation of carotid body chemoreceptors in a manner suggesting a cardiac destination, and had conduction velocities similar to those reported for cardio-inhibitory vagus efferent fibres (Hassan et al 1987a).…”

Section: Discussionmentioning

confidence: 99%

“…The nature of the response of efferent vagus nerves indicated that their likely destination was the heart (e.g. Jewett, 1964;Neil, 1979). Initially, the responsive fibres were examined during distension of the bladder for 90 s and during an increase in carotid sinus pressure for 90 s. The same protocol was used in studying some of the efferent vagus nerve fibres which did not respond to an increase in carotid sinus pressure.…”

Section: Experimental Protocolmentioning

confidence: 99%

The Effect of Distension of the Urinary Bladder on Activity in Efferent Vagal Fibres in Anaesthetized Dogs

1989

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SUMMARYExperiments were performed in anaesthetized dogs to find out whether the response of decreases in vagus nerve activity to distension of the urinary bladder is affected by changes in carotid sinus pressure. The carotid sinuses were vascularly isolated and perfused with blood at constant flow. Both ureters were cannulated and the urinary bladder was distended with warm Ringer solution. In eight dogs, all eleven efferent vagus fibres which responded to changes in carotid sinus pressure also responded to distension of the urinary bladder by a decrease in activity. This response of a decrease in activity was obtained at all levels of carotid sinus pressure between 8 4 and 30 kPa, and was greater at high than at low carotid sinus pressure. In the same vagus fibres, a relation was shown between progressive decreases in activity and either increases in intravesical pressure up to 8-7 kPa or reductions in carotid sinus pressure between 9 and 30 kPa. The decreases in activity were greater at high than at low carotid sinus pressure. These findings have shown that the inhibition of vagus nerve activity caused by bladder distension was affected by the level of carotid sinus pressure.

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Activity of single efferent fibres in the cervical vagus nerve of the dog, with special reference to possible cardio‐inhibitory fibres

Cited by 191 publications

References 44 publications

Ventriculophasic Modulation of Atrioventricular Nodal Conduction in Humans

Ventriculophasic Modulation of Atrioventricular Nodal Conduction in Humans

An electrophysiological study of single vagal efferent units associated with gastric movements in sheep

The Effect of Distension of the Urinary Bladder on Activity in Efferent Vagal Fibres in Anaesthetized Dogs

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