Increased vasomotor sympathetic nerve activity and decreased plasma nitric oxide release after head-down bed rest in humans: Disappearance of correlation between vasoconstrictor and vasodilator

Atsunori Kamiya, Satoshi Iwase, Daisaku Michikami, Qi Fu, Tadaaki Mano, Kiyoyuki Kitaichi, Kenji Takagi

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

We hypothesized that the relationship between resting levels of sympathetic vasoconstrictor nerve traffic and dilator substance nitric oxide (NO) release is altered after exposure to microgravity, resulting in abnormal peripheral resistance. To examine the hypothesis, we assessed muscle sympathetic nerve activity (MSNA) (microneurography), an indicator of NO release (plasma nitrite/nitrate concentrations) and leg vascular resistance (venous occlusion plethysmography) in 20 healthy male volunteers before and after 14 days of 6°head-down bed rest (HDBR), the ground-based analogue of microgravity. MSNA increased, while plasma nitrite/nitrate concentrations decreased after HDBR. A significant positive correlation observed between MSNA and plasma nitrite/nitrate concentrations before HDBR disappeared after HDBR. Leg vascular resistance increased after HDBR. In conclusion, an imbalance between sympathetic vasoconstrictor traffic and NO release might contribute to elevated peripheral vascular resistance following HDBR. (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish
Pages (from-to)21-24
Number of pages4
JournalNeuroscience Letters
Volume281
Issue number1
DOIs
Publication statusPublished - Mar 3 2000
Externally publishedYes

Keywords

  • Bed rest
  • Microneurography
  • Muscle sympathetic nerve activity
  • Vascular resistance
  • Vasoconstrictor
  • Vasodilator

ASJC Scopus subject areas

  • Neuroscience(all)

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