Journal ArticleDOI
Circulatory effects of interruption and stimulation of cardiac vagal afferents.
B. ÖBerg,Saxon William White +1 more
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The influence of the rhythmic activity in cardiac vagal afferents on the circulation was analyzed in chloralose-anesthetized cats by observing the cardiovascular responses to sudden interruption of this activity and to afferent stimulation of the cardiac nerves.Abstract:
The influence of the rhythmic activity in cardiac vagal afferents on the circulation was analyzed in chloralose-anesthetized cats by observing the cardiovascular responses to sudden interruption of this activity and to afferent stimulation of the cardiac nerves. The evoked responses were compared with those produced by “unloading” and stimulation of arterial baroreceptors. — Elimination of the impulse traffic in vagal afferents produced a blood pressure rise, a tachycardia and vasoconstrictions in skeletal muscle, intestine and kidney, indicating a tonic restraint of these afferents on the medullary vasomotor centre. The responses were generally moderate in the presence of normally functioning arterial baroreceptors but were pronounced after elimination of “buffering” influences from these receptors. — Comparisons of the inhibitory influences from vagal cardiac afferents and baroreceptor afferents, respectively, on the vasomotor centre indicated that the former were preferentially directed to neurons controlling the efferent discharge to the heart and the renal vessels. There was no evidence for a particularly strong engagement of the capacitance vessels in reflex patterns mediated through cardiac afferents. — Low frequency afferent stimulation of the cardiac nerves generally induced a profound brady-cardia, which was probably due to stimulation of fibres not normally tonically active.read more
Citations
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Journal ArticleDOI
Increase of sympathetic discharge to skeletal muscle but not to skin during mild lower body negative pressure in humans.
TL;DR: These findings challenge the concept that the cutaneous circulation participates importantly in the peripheral circulatory adjustments to unloading of cardiopulmonary afferents during orthostatic stress in humans.
Journal ArticleDOI
Circulatory Responses to Stimulation of Medullated and Non-medullated Afferents in the Cardiac Nerve in the Cat
Bengt ÖBerg,Peter Thorén +1 more
TL;DR: The results suggest that the powerful reflex influence from cardiac receptors on the cardiovascular system is exerted by receptors with non-medullated afferents, while endings firing in medullated pathways as e.g. atrial receptors, have very small direct effects on theiovascular system and then rather of an excitatory nature.
Journal ArticleDOI
Vagal afferent modulation of a nociceptive reflex in rats: involvement of spinal opioid and monoamine receptors
TL;DR: Cervical VAS engages a spinal opioid system and co-activates descending serotonergic and noradrenergic systems to modulate spinal nociceptive processing and suggest that excitation of high-threshold, unmyelinated fibers are important in VAS-induced descending inhibition.
Journal ArticleDOI
Relation between sympathetic outflow and vascular resistance in the calf during perturbations in central venous pressure. Evidence for cardiopulmonary afferent regulation of calf vascular resistance in humans.
TL;DR: The present findings strongly suggest that the stimulation of skeletal muscleu sympathetic outflow caused mainly by unloading of cardiopulmonary afferents is an important atonomic adjustment to orthostatic stress.
Book ChapterDOI
Reflex control of the human cardiovascular system
John T. Shepherd,Giuseppe Mancia +1 more
TL;DR: The surge of knowledge about the autonomic regulation of the human cardiovascular system which commenced in the 1940s was a consequence of many events, including the information gained from animal studies of the various reflexogenic zones which modulate the circulation.
References
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Journal Article
Comparative studies on the adrenergic neuro-hormonal control of resistance and capacitance blood vessels in the cat.
Journal ArticleDOI
Vagal Afferent Fibres
TL;DR: The cervical vagus consists of about 30 thousand fibres of which about 24 000 are sensory in function and about 3 thousand are myelinated and have been the centre of attraction in electrophysiological studies chiefly owing to the relative ease with which impulses can be recorded in them.
Journal ArticleDOI
A study of right and left atrial receptors.
TL;DR: It will be shown that all such receptors encountered so far arose in the right and left atria of the heart; these will be referred to as type B atrial receptors.
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