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The effect of baroreceptors on the latency of evoked responses in sympathetic nerves during the cardiac cycle
Author(s) -
Fussey I. F.,
Kidd C.,
Whitwam J. G.
Publication year - 1973
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1973.sp010156
Subject(s) - baroreceptor , efferent , cardiac cycle , carotid sinus , medicine , reflex , stimulation , blood pressure , latency (audio) , heart rate , afferent , electrical engineering , engineering
1. A rapid increase in pressure in a vascularly isolated perfused carotid sinus has been shown to inhibit a reflex response in efferent sympathetic nerves of the dog evoked by electrical stimulation of the radial nerve. 2. In intact preparations with the carotid baroreceptors innervated, the mean latency and the variance of the latency of reflex sympathetic nerve responses was reduced when the stimuli evoking the responses were applied at one point of both cardiac and respiratory cycles. When the baroreceptors were denervated there were no significant differences in the responses to random and synchronized stimuli. 3. In intact preparations the latency of evoked responses in sympathetic nerves was found to vary progressively during a cardiac cycle; the maximum increase in latency was observed with the responses that occurred at that phase of the cardiac cycle when the baroreceptors exert maximal inhibition on spontaneous sympathetic activity. After denervation of the carotid sinuses a much smaller change during the cardiac cycle was still present, possibly due to effects produced by baroreceptors of the aortic arch and elsewhere. 4. It was concluded that changes in baroreceptor activity, due to beat to beat fluctuations of the systemic arterial pressure are a major factor causing variations in the latency of responses in sympathetic nerves evoked by stimuli applied to a cutaneous nerve.