| Ventilatory restraint of sympathetic activity during chemoreflex stress. | |
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MedLine Citation:
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PMID: 20826706 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The within-breath modulation of muscle sympathetic nerve activity (MSNA) is well established, with greater activity occurring during expiration and less during inspiration. Whether ventilation per se affects the longer-term (i.e., minute-to-minute) regulation of MSNA has not been determined. We sought to define the specific role of ventilation in regulating sympathetic activation during chemoreflex activation, where both ventilation and MSNA are increased. Ten young healthy subjects performed both asphyxic rebreathing and repeated, rebreathing apneas to cause the same magnitude of chemoreflex stress in the presence or absence of ventilation. Both protocols caused increases in sympathetic burst frequency, burst amplitude, and burst incidence. However, burst frequency was increased more during repeated apneas (12 ± 6 to 25 ± 7 bursts/min) compared with rebreathing (12 ± 5 to 17 ± 7 bursts/min; P < 0.001) due to a greater burst incidence during apneas (36 ± 11 bursts/100 heart beats) vs. rebreathing (26 ± 8 bursts/100 heart beats, P < 0.001). The sympathetic gain to chemoreflex stress was also larger during repeated apneas (2.29 ± 1.29 au/% desaturation) compared with rebreathing (1.44 ± 0.53 au/% desaturation, P < 0.05). The augmented sympathetic response during apneas was associated with a larger pressor response and total peripheral resistance compared with rebreathing. These data demonstrate that ventilation per se restrains sympathetic activation during chemoreflex activation. Further, the augmented sympathetic response during apneas was associated with greater cardiovascular stress and may be relevant to the cardiovascular pathology associated with sleep-disordered breathing. |
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Authors:
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Craig D Steinback; Toni Breskovic; Maria Frances; Zeljko Dujic; J Kevin Shoemaker |
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Publication Detail:
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Type: Journal Article; Multicenter Study; Randomized Controlled Trial; Research Support, Non-U.S. Gov't Date: 2010-09-08 |
Journal Detail:
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Title: American journal of physiology. Regulatory, integrative and comparative physiology Volume: 299 ISSN: 1522-1490 ISO Abbreviation: Am. J. Physiol. Regul. Integr. Comp. Physiol. Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-11-03 Completed Date: 2010-12-01 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901230 Medline TA: Am J Physiol Regul Integr Comp Physiol Country: United States |
Other Details:
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Languages: eng Pagination: R1407-14 Citation Subset: IM |
Affiliation:
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Neurovascular Research Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Apnea / metabolism, physiopathology* Baroreflex Blood Pressure Chemoreceptor Cells / metabolism* Croatia Heart Rate Humans Male Neural Inhibition* Ontario Peroneal Nerve / physiopathology Pulmonary Ventilation* Respiratory Mechanics Stress, Physiological* Sympathetic Nervous System / physiopathology* Time Factors Vascular Resistance Young Adult |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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