Effects of three days of dry immersion on muscle sympathetic nerve activity and arterial blood pressure in humans

Satoshi Iwase, Yoshiki Sugiyama, Chihiro Miwa, Atsunori Kamiya, Tadaaki Mano, Yoshinobu Ohira, Boris Shenkman, Anatoly I. Egorov, Inessa B. Kozlovskaya

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

The present study was performed to determine how sympathetic function is altered by simulated microgravity, dry immersion for 3 days, and to elucidate the mechanism of post-spaceflight orthostatic intolerance in humans. Six healthy men aged 21-36 years old participated in the study. Before and after the dry immersion, subjects performed head-up tilt (HUT) test to 30°and 60° (5 min each) with recordings of muscle sympathetic nerve activity (MSNA, by microneurography), electrocardiogram, and arterial blood pressure (Finapres). Resting MSNA was increased after dry immersion from 23.7±3.2 to 40.9±3.0 bursts/min (p<0.005) without significant changes in resting heart rate (HR). MSNA responsiveness to orthostasis showed no significant difference but HR response was significantly augmented after dry immersion (p<0.005). A significant diastolic blood pressure fall at 5th min of 60°HUT was observed in five orthostatic tolerant subjects despite enough MSNA discharge after dry immersion. A subject suffered from presyncope at 2 min after 60°HUT. He showed gradual blood pressure fall 10 s after 60°HUT with initially well-maintained MSNA response and then with a gradually attenuated MSNA, followed by a sudden MSNA withdrawal and abrupt blood pressure drop. In conclusion, dry immersion increased MSNA without changing MSNA response to orthostasis, and resting HR, while increasing the HR response to orthostasis. Analyses of MSNA and blood pressure changes in orthostatic tolerant subjects and a subject with presyncope suggested that not only insufficient vasoconstriction to sympathetic stimuli, but also a central mechanism to induce a sympathetic withdrawal might play a role in the development of orthostatic intolerance after microgravity exposure. Copyright (C) 2000 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)156-164
Number of pages9
JournalJournal of the Autonomic Nervous System
Volume79
Issue number2-3
DOIs
Publication statusPublished - Mar 15 2000
Externally publishedYes

Fingerprint

Immersion
Arterial Pressure
Muscles
Blood Pressure
Dizziness
Heart Rate
Orthostatic Intolerance
Weightlessness
Syncope
Space Flight
Vasoconstriction
Electrocardiography
Head

Keywords

  • Head-up tilt
  • Microneurography
  • Muscle sympathetic nerve activity
  • Orthostatic intolerance

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology
  • Clinical Neurology

Cite this

Effects of three days of dry immersion on muscle sympathetic nerve activity and arterial blood pressure in humans. / Iwase, Satoshi; Sugiyama, Yoshiki; Miwa, Chihiro; Kamiya, Atsunori; Mano, Tadaaki; Ohira, Yoshinobu; Shenkman, Boris; Egorov, Anatoly I.; Kozlovskaya, Inessa B.

In: Journal of the Autonomic Nervous System, Vol. 79, No. 2-3, 15.03.2000, p. 156-164.

Research output: Contribution to journalArticle

Iwase, Satoshi ; Sugiyama, Yoshiki ; Miwa, Chihiro ; Kamiya, Atsunori ; Mano, Tadaaki ; Ohira, Yoshinobu ; Shenkman, Boris ; Egorov, Anatoly I. ; Kozlovskaya, Inessa B. / Effects of three days of dry immersion on muscle sympathetic nerve activity and arterial blood pressure in humans. In: Journal of the Autonomic Nervous System. 2000 ; Vol. 79, No. 2-3. pp. 156-164.
@article{6c811eb154e8445fa5c1c6d17ac541f0,
title = "Effects of three days of dry immersion on muscle sympathetic nerve activity and arterial blood pressure in humans",
abstract = "The present study was performed to determine how sympathetic function is altered by simulated microgravity, dry immersion for 3 days, and to elucidate the mechanism of post-spaceflight orthostatic intolerance in humans. Six healthy men aged 21-36 years old participated in the study. Before and after the dry immersion, subjects performed head-up tilt (HUT) test to 30°and 60° (5 min each) with recordings of muscle sympathetic nerve activity (MSNA, by microneurography), electrocardiogram, and arterial blood pressure (Finapres). Resting MSNA was increased after dry immersion from 23.7±3.2 to 40.9±3.0 bursts/min (p<0.005) without significant changes in resting heart rate (HR). MSNA responsiveness to orthostasis showed no significant difference but HR response was significantly augmented after dry immersion (p<0.005). A significant diastolic blood pressure fall at 5th min of 60°HUT was observed in five orthostatic tolerant subjects despite enough MSNA discharge after dry immersion. A subject suffered from presyncope at 2 min after 60°HUT. He showed gradual blood pressure fall 10 s after 60°HUT with initially well-maintained MSNA response and then with a gradually attenuated MSNA, followed by a sudden MSNA withdrawal and abrupt blood pressure drop. In conclusion, dry immersion increased MSNA without changing MSNA response to orthostasis, and resting HR, while increasing the HR response to orthostasis. Analyses of MSNA and blood pressure changes in orthostatic tolerant subjects and a subject with presyncope suggested that not only insufficient vasoconstriction to sympathetic stimuli, but also a central mechanism to induce a sympathetic withdrawal might play a role in the development of orthostatic intolerance after microgravity exposure. Copyright (C) 2000 Elsevier Science B.V.",
keywords = "Head-up tilt, Microneurography, Muscle sympathetic nerve activity, Orthostatic intolerance",
author = "Satoshi Iwase and Yoshiki Sugiyama and Chihiro Miwa and Atsunori Kamiya and Tadaaki Mano and Yoshinobu Ohira and Boris Shenkman and Egorov, {Anatoly I.} and Kozlovskaya, {Inessa B.}",
year = "2000",
month = "3",
day = "15",
doi = "10.1016/S0165-1838(99)00076-4",
language = "English",
volume = "79",
pages = "156--164",
journal = "Autonomic Neuroscience: Basic and Clinical",
issn = "1566-0702",
publisher = "Elsevier",
number = "2-3",

}

TY - JOUR

T1 - Effects of three days of dry immersion on muscle sympathetic nerve activity and arterial blood pressure in humans

AU - Iwase, Satoshi

AU - Sugiyama, Yoshiki

AU - Miwa, Chihiro

AU - Kamiya, Atsunori

AU - Mano, Tadaaki

AU - Ohira, Yoshinobu

AU - Shenkman, Boris

AU - Egorov, Anatoly I.

AU - Kozlovskaya, Inessa B.

PY - 2000/3/15

Y1 - 2000/3/15

N2 - The present study was performed to determine how sympathetic function is altered by simulated microgravity, dry immersion for 3 days, and to elucidate the mechanism of post-spaceflight orthostatic intolerance in humans. Six healthy men aged 21-36 years old participated in the study. Before and after the dry immersion, subjects performed head-up tilt (HUT) test to 30°and 60° (5 min each) with recordings of muscle sympathetic nerve activity (MSNA, by microneurography), electrocardiogram, and arterial blood pressure (Finapres). Resting MSNA was increased after dry immersion from 23.7±3.2 to 40.9±3.0 bursts/min (p<0.005) without significant changes in resting heart rate (HR). MSNA responsiveness to orthostasis showed no significant difference but HR response was significantly augmented after dry immersion (p<0.005). A significant diastolic blood pressure fall at 5th min of 60°HUT was observed in five orthostatic tolerant subjects despite enough MSNA discharge after dry immersion. A subject suffered from presyncope at 2 min after 60°HUT. He showed gradual blood pressure fall 10 s after 60°HUT with initially well-maintained MSNA response and then with a gradually attenuated MSNA, followed by a sudden MSNA withdrawal and abrupt blood pressure drop. In conclusion, dry immersion increased MSNA without changing MSNA response to orthostasis, and resting HR, while increasing the HR response to orthostasis. Analyses of MSNA and blood pressure changes in orthostatic tolerant subjects and a subject with presyncope suggested that not only insufficient vasoconstriction to sympathetic stimuli, but also a central mechanism to induce a sympathetic withdrawal might play a role in the development of orthostatic intolerance after microgravity exposure. Copyright (C) 2000 Elsevier Science B.V.

AB - The present study was performed to determine how sympathetic function is altered by simulated microgravity, dry immersion for 3 days, and to elucidate the mechanism of post-spaceflight orthostatic intolerance in humans. Six healthy men aged 21-36 years old participated in the study. Before and after the dry immersion, subjects performed head-up tilt (HUT) test to 30°and 60° (5 min each) with recordings of muscle sympathetic nerve activity (MSNA, by microneurography), electrocardiogram, and arterial blood pressure (Finapres). Resting MSNA was increased after dry immersion from 23.7±3.2 to 40.9±3.0 bursts/min (p<0.005) without significant changes in resting heart rate (HR). MSNA responsiveness to orthostasis showed no significant difference but HR response was significantly augmented after dry immersion (p<0.005). A significant diastolic blood pressure fall at 5th min of 60°HUT was observed in five orthostatic tolerant subjects despite enough MSNA discharge after dry immersion. A subject suffered from presyncope at 2 min after 60°HUT. He showed gradual blood pressure fall 10 s after 60°HUT with initially well-maintained MSNA response and then with a gradually attenuated MSNA, followed by a sudden MSNA withdrawal and abrupt blood pressure drop. In conclusion, dry immersion increased MSNA without changing MSNA response to orthostasis, and resting HR, while increasing the HR response to orthostasis. Analyses of MSNA and blood pressure changes in orthostatic tolerant subjects and a subject with presyncope suggested that not only insufficient vasoconstriction to sympathetic stimuli, but also a central mechanism to induce a sympathetic withdrawal might play a role in the development of orthostatic intolerance after microgravity exposure. Copyright (C) 2000 Elsevier Science B.V.

KW - Head-up tilt

KW - Microneurography

KW - Muscle sympathetic nerve activity

KW - Orthostatic intolerance

UR - http://www.scopus.com/inward/record.url?scp=0033976224&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033976224&partnerID=8YFLogxK

U2 - 10.1016/S0165-1838(99)00076-4

DO - 10.1016/S0165-1838(99)00076-4

M3 - Article

C2 - 10699647

AN - SCOPUS:0033976224

VL - 79

SP - 156

EP - 164

JO - Autonomic Neuroscience: Basic and Clinical

JF - Autonomic Neuroscience: Basic and Clinical

SN - 1566-0702

IS - 2-3

ER -