Endogenous angiotensin II does not contribute to sympathetic venoconstriction in dorsal hand veins of healthy humans

S Masumori, D E Newby, F E Strachan, N A Boon, D J Webb

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: Sympathetically mediated venoconstriction is augmented by exogenously administered angiotensin II. This study was designed to assess whether endogenous angiotensin II influences sympathetically mediated venous tone.

METHODS: Responses of dorsal hand veins to local intravenous administration of subsystemic doses of losartan, an angiotensin II type-1 receptor antagonist, were assessed with use of a well-validated displacement technique in eight healthy male volunteers. In a four-phase study, responses to local infusions of angiotensin II (4 to 64 ng/min) and norepinephrine (1 to 128 ng/min) or to sympathetic venoconstriction produced by a single deep breath were compared in the presence of either saline placebo or 30 microg/min losartan. Each phase of the study was conducted on a separate day, in random order, and each phase was separated by at least 1 week.

RESULTS: Angiotensin II (p = 0.03) and norepinephrine (p < 0.001) caused dose-dependent venoconstriction. Losartan attenuated the venoconstriction induced by angiotensin II (p = 0.048) but had no effect on the responses to norepinephrine or the venoconstriction induced by a single deep breath.

CONCLUSIONS: In contrast to exogenously administered angiotensin II, basal endogenous angiotensin II does not influence sympathetically mediated venoconstriction in healthy humans. However, endogenous angiotensin II may have a role in circumstances of renin-angiotensin system activation, such as salt depletion.

Original languageEnglish
Pages (from-to)327-333
Number of pages7
JournalClinical pharmacology and therapeutics
Volume62
Issue number3
DOIs
Publication statusPublished - Sep 1997

Keywords

  • Adrenergic alpha-Agonists
  • Adult
  • Angiotensin Receptor Antagonists
  • Antihypertensive Agents
  • Area Under Curve
  • Hand
  • Humans
  • Infusions, Intravenous
  • Losartan
  • Male
  • Norepinephrine
  • Receptors, Angiotensin
  • Renin-Angiotensin System
  • Single-Blind Method
  • Vasoconstriction
  • Veins

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