In:
The Journal of Physiology, Wiley, Vol. 594, No. 19 ( 2016-10), p. 5611-5627
Abstract:
We studied healthy supine astronauts on Earth with electrocardiogram, non‐invasive arterial pressure, respiratory carbon dioxide concentrations, breathing depth and sympathetic nerve recordings. The null hypotheses were that heart beat interval fluctuations at usual breathing frequencies are baroreflex mediated, that they persist during apnoea, and that autonomic responses to apnoea result from changes of chemoreceptor, baroreceptor or lung stretch receptor inputs. R‐R interval fluctuations at usual breathing frequencies are unlikely to be baroreflex mediated, and disappear during apnoea. The subjects’ responses to apnoea could not be attributed to changes of central chemoreceptor activity (hypocapnia prevailed); altered arterial baroreceptor input (vagal baroreflex gain declined and muscle sympathetic nerve burst areas, frequencies and probabilities increased, even as arterial pressure climbed to new levels); or altered pulmonary stretch receptor activity (major breathing frequency and tidal volume changes did not alter vagal tone or sympathetic activity). Apnoea responses of healthy subjects may result from changes of central respiratory motoneurone activity.
Type of Medium:
Online Resource
ISSN:
0022-3751
,
1469-7793
DOI:
10.1113/tjp.2016.594.issue-19
Language:
English
Publisher:
Wiley
Publication Date:
2016
detail.hit.zdb_id:
1475290-6
SSG:
12
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