Vasoactive Neuroendocrine Responses Associated with Tolerance to Lower Body Negative Pressure in Humans

Abstract

The purpose of this investigation was to test the hypothesis that peripheral vasoconstriction and orthostatic tolerance are associated with increased circulating plasma concentrations of noradrenaline, vasopressin and renin angiotensin. Sixteen men were categorized as having high (HT, n = 9) or low (LT, n = 7) tolerance to lower body negative pressure (LBNP) based on whether the endpoint of their pre-syncopal-limited LBNP (peak LBNP) exposure exceeded ) 60 mmHg. The two groups were matched for age, height, weight, leg volume, blood volume and maximal oxygen uptake, as well as baseline blood volume and plasma concentrations of vasoactive hormones. Peak LBNP induced similar reductions in mean arterial pressure in both groups.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 2000
Accession Number
ADA628400

Entities

People

  • T. M. Sather
  • Víctor A. Convertino

Organizations

  • United States Army Institute of Surgical Research

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Biological Sciences
  • Blood Volume
  • Cardiovascular Physiological Phenomena
  • Chemical Synthesis
  • Chemistry
  • Consciousness Disorders
  • Heart Rate
  • Hormones
  • Hypotension
  • Medical Personnel
  • New York
  • Norepinephrine
  • Physiology
  • Pituitary And Hypothalamic Hormones And Analogues
  • Secretion
  • United States
  • Vascular Diseases

Fields of Study

  • Medicine

Readers

  • Cardiovascular Physiology
  • Gender and Food Studies