In vivo modulation of norepinephrine-induced cerebral oxygenation states by hypoxia and hyperoxia.

Published

Journal Article

The effect of intravenous norepinephrine (NE) administration on three O2-dependent parameters of cerebral oxygenation was studied in the parietal cortex of skull intact anesthetized rats. Reflectance spectrophotometry was used to measure in vivo changes in cortical hemoglobin saturation (Hb/HbO2), blood volume (BV), and cytochrome c oxidase (cyt. a,a3) oxidation-reduction state. The influence of arterial pressure of oxygen (paO2) on norepinephrine-induced changes in cortical microcirculatory O2 delivery and cyt. a,a3 redox state was tested under conditions of normoxia, hypoxia, and hyperoxia. Norepinephrine produced cyt. a,a3 redox changes which were independent of compensatory alterations in cortical blood volume and changes in systemic blood pressure at the tested physiological extremes. During normoxia, NE caused dose-dependent systemic pressure-related increases in the oxidation level of cyt. a,a3. Conversely, in hypoxia NE caused a reduction. Microcirculatory and cyt. a,a3 redox responses to low doses of NE during hyperoxia were similar to those obtained at high doses during normoxia. The kinetic pattern of changes in hemoglobin saturation, cyt. a,a3 redox state, and cortical blood volume during normoxia and hypoxia was consistent with direct alteration in oxygen delivery to the respiratory chain and possible modification of cerebral oxidative metabolism. Blood-brain barrier alterations and vascular smooth muscle resistance changes to NE under tested conditions of oxygenation are postulated to be responsible for the observed results.

Full Text

Duke Authors

Cited Authors

  • Sylvia, AL; Piantadosi, CA

Published Date

  • July 15, 1985

Published In

Volume / Issue

  • 338 / 2

Start / End Page

  • 281 - 288

PubMed ID

  • 2992687

Pubmed Central ID

  • 2992687

International Standard Serial Number (ISSN)

  • 0006-8993

Digital Object Identifier (DOI)

  • 10.1016/0006-8993(85)90158-1

Language

  • eng

Conference Location

  • Netherlands