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Influence of respiratory motor neurone activity on human autonomic and haemodynamic rhythmsAlthough humans hold great advantages over other species as subjects for biomedical research, they also bring major disadvantages. One is that among the many rhythmic physiological signals that can be recorded, there is no sure way to know which individual change precedes another, or which change represents cause and which represents effect. In an attempt to deal with the inherent complexity of research conducted in intact human subjects, we developed and used a structural equation model to analyse responses of healthy young men to pharmacological changes of arterial pressure and graded inspiratory resistance, before and after vagomimetic atropine. Our model yielded a good fit of the experimental data, with a system weighted R2 of 0.77, and suggested that our treatments exerted both direct and indirect influences on the variables we measured. Thus, infusions of nitroprusside and phenylephrine exerted all of their direct effects by lowering and raising arterial pressure; the changes of R-R intervals, respiratory sinus arrhythmia and arterial pressure fluctuations that these drugs provoked, were indirect consequences of arterial pressure changes. The only direct effect of increased inspiratory resistance was augmentation of arterial pressure fluctuations. These results may provide a new way to disentangle and understand responses of intact human subjects to experimental forcings. The principal new insight we derived from our modelling is that respiratory gating of vagal-cardiac motor neurone firing is nearly maximal at usual levels of arterial pressure and inspiratory motor neurone activity.
Document ID
20040112411
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Gonschorek, A. S.
(Department of Neurology Berufsgenossenschaftliches Unfallkrankenhaus Hamburg, Hamburg, Germany)
Lu, L. L.
Halliwill, J. R.
Beightol, L. A.
Taylor, J. A.
Painter, J. A.
Warzel, H.
Eckberg, D. L.
Date Acquired
August 21, 2013
Publication Date
May 1, 2001
Publication Information
Publication: Clinical physiology (Oxford, England)
Volume: 21
Issue: 3
ISSN: 0144-5979
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: HL22296
CONTRACT_GRANT: HL30506
CONTRACT_GRANT: HL07556
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Cardiopulmonary

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