Transcutaneous vagal nerve stimulation during lower body negative pressure.

Autor: Petersen JCG; Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Cambridge, MA, USA. Electronic address: cgpeters@mit.edu., Becker R; University of California Davis, Sacramento, CA, USA., Petersen LG; Harvard Medical School, Cambridge, MA, USA; Massachusetts Institute of Technology, Cambridge, MA, USA; University of Copenhagen, Denmark.
Jazyk: angličtina
Zdroj: Autonomic neuroscience : basic & clinical [Auton Neurosci] 2024 Aug; Vol. 254, pp. 103192. Date of Electronic Publication: 2024 Jun 02.
DOI: 10.1016/j.autneu.2024.103192
Abstrakt: Background: Para-sympathetic vagal activation has profound influence on heart rate and other cardiovascular parameters. We tested the hypothesis that transcutaneous Vagal Nerve Stimulation (tVNS) through the auricular branch of the vagus nerve would attenuate the normal sympathetic response to central blood volume reduction by lower body negative pressure (LBNP).
Method: 10 healthy volunteers (6 female; age 21 ± 2 years; weight 62 ± 13 kg; height 167 ± 12 cm) were included in this cross-over design trial. After 15 min rest in supine position, subjects underwent three 15-min periods of 30 mmHg LBNP intervention with and without cyclic tVNS stimulation. Continuous cardiovascular parameters (Nexfin) were recorded.
Results: Overall tVNS did not convincingly attenuate sympathetic response to central hypovolemia. Deactivation of the tVNS during LBNP resulted in increased MAP at 2.3 ± 0.5 mmHg (P < 0.001). Comparing the cyclic actual active stimulation periods to periods with pause during tVNS intervention showed a decrease in HR by 72.9 ± 11.2 to 70.2 ± 11.6 bpm (mean ± SD; P < 0.05), and concomitant increases in SV (86.0 ± 12.1 to 87.2 ± 12.6 mL; P < 0.05), MAP (82.9 ± 6.3 to 84.0 ± 6.2 mmHg; P < 0.05) and TPR (1116.0 ± 111.1 to 1153 ± 104.8 dyn*s/cm5; P < 0.05).
Conclusion: tVNS in 30 s cycles during LBNP can selectively attenuate HR, prompting a compensatory augmented sympathetic response. It would appear the method used in this study at least, has an isolated cardiac inhibitory effect probably mediated by augmented vagal activity on the sinoatrial or atrio-ventricular node, possibly in combination with reduced activity in the sympathetic cardiac nerve.
Competing Interests: Declaration of competing interest The authors have no competing interests.
(Copyright © 2024 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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