Reflex discharge patterns of cardiac vagal efferent fibres
- 1 April 1972
- journal article
- Published by Wiley in The Journal of Physiology
- Vol. 222 (1), 1-15
- https://doi.org/10.1113/jphysiol.1972.sp009784
Abstract
1. Unit activity was recorded from single and few fibre preparations in a cardiac branch of the right vagus nerve of the cat.2. Increases in blood pressure mediated solely by the right carotid sinus nerve produced bradycardia when all other nerves to the heart had been cut. Myelinated fibres in the cardiac branch of the right vagus nerve were reflexly activated by the same procedure.3. The fibres were silent when blood pressure was below 140-150 mm Hg. As the pressure began to rise, they discharged phasically with the cardiac cycle. At pressures greater than 180 mm Hg, the discharge was continuous attaining maximum rates of 40/sec.4. Stimulation of carotid body chemoreceptors also reflexly excited these fibres, as did stimulation of baroreceptors in both the left carotid sinus and aortic arch. Afferent fibres in the left vagus discharging in response to changes in blood pressure reflexly excited the cardiac efferent fibres. Increases in phrenic motoneurone discharge coincided with inhibition of these fibres. Electrical stimulation of the glossopharyngeal nerve also produced inhibition.Keywords
This publication has 19 references indexed in Scilit:
- Termination and secondary projections of carotid sinus nerve in the cat brain stemAmerican Journal of Physiology-Legacy Content, 1969
- Preserved vagal visceromotor function following destruction of the dorsal motor nucleusThe Journal of Physiology, 1969
- The localization of the first synapse in the carotid sinus baroreceptor reflex pathway and its alteration of the afferent inputPflügers Archiv - European Journal of Physiology, 1969
- Effects on heart rate of electrical stimulation of medullary vagal structures in the catThe Journal of Physiology, 1965
- Electrical activity of efferent vagal fibres and dorsal nucleus of the vagus during reflex bradycardia in the catThe Journal of Physiology, 1965
- RESPIRATORY + CARDIOVASCULAR RESPONSES OF TEMPORALLY SEPARATED AORTIC + CAROTID BODIES TO CYANIDE NICOTINE PHENYLDIGUANIDE + SEROTONIN1964
- ACTIVITY OF SINGLE VAGAL FIBERS EFFERENT TO THE HEARTThe Japanese Journal of Physiology, 1964
- The effects of stimulation of the carotid body chemoreceptors on heart rate in the dogThe Journal of Physiology, 1958
- The conduction velocities of respiratory and cardiovascular afferent fibres in the vagus nerveThe Journal of Physiology, 1953
- The Effect of Certain Autonomic Drugs on the Action Potentials of the Sinus NerveActa Physiologica Scandinavica, 1952