Journal article
Epinephrine facilitates neurogenic vasoconstriction in humans
The Journal of clinical investigation, Vol.81(4), pp.1265-1274
04/1988
DOI: 10.1172/JCI113444
PMCID: PMC329658
PMID: 3350973
Abstract
Numerous studies have suggested that epinephrine may facilitate neural release of NE. There have been no studies in humans that demonstrate the functional significance of this action. To determine whether epinephrine facilitates neurogenic vasoconstriction in humans, we contrasted forearm vasoconstrictor responses to a reflex stimulus (lower body negative pressure [LBNP]) and to intraarterial NE before, during, and 30 min after infusion of epinephrine (50 ng/min) or isoproterenol (10 or 25 ng/min) into a brachial artery. These doses had no systemic effects. We reasoned that if prejunctional stimulation of beta receptors by epinephrine and isoproterenol had functional significance, the vasoconstrictor response to LBNP would be potentiated in comparison to the response to NE (postjunctional mechanism). Studies were done on 23 normal male volunteers. Forearm blood flow was measured with a strain gauge plethysmograph and intraarterial pressure was recorded. The ratio of vasoconstrictor responses to LBNP/NE was used as an index of neural release of the neurotransmitter NE. This ratio increased during infusions of both epinephrine and isoproterenol. 30 min after epinephrine the vasoconstrictor response to LBNP (n = 15) was augmented from +9.9 +/- 2.2 (SE) resistance units (RU) before epinephrine to +16.4 +/- 3.2 RU (P less than 0.05); whereas the response to NE (n = 8) tended to decrease from +8.8 +/- 3.1 RU before to +4.2 +/- 1.2 RU after epinephrine (P greater than 0.05). In contrast, 30 min after isoproterenol the vasoconstrictor responses to LBNP and NE were the same as before isoproterenol. The augmented ratio of responses to LBNP/NE after epinephrine and not after isoproterenol supports the concept that epinephrine, but not isoproterenol, is taken up by the adrenergic terminal, is released subsequently during reflex stimulation, and augments the release of the neurotransmitter NE. These experiments provide the first hemodynamic evidence in humans that epinephrine and isoproterenol facilitate neurogenic vasoconstriction. The sustained effect of epinephrine in contrast to isoproterenol suggests that the late facilitation by epinephrine is related to its neural uptake and subsequent release.
Details
- Title: Subtitle
- Epinephrine facilitates neurogenic vasoconstriction in humans
- Creators
- John S Floras - Department of Internal Medicine, University of Iowa College of Medicine, University of Iowa Hospitals and Clinics, Iowa City 52242Philip E Aylward - Department of Internal Medicine, University of Iowa College of Medicine, University of Iowa Hospitals and Clinics, Iowa City 52242Ronald G Victor - Department of Internal Medicine, University of Iowa College of Medicine, University of Iowa Hospitals and Clinics, Iowa City 52242Allyn L Mark - Department of Internal Medicine, University of Iowa College of Medicine, University of Iowa Hospitals and Clinics, Iowa City 52242Francois M Abboud - Department of Internal Medicine, University of Iowa College of Medicine, University of Iowa Hospitals and Clinics, Iowa City 52242
- Resource Type
- Journal article
- Publication Details
- The Journal of clinical investigation, Vol.81(4), pp.1265-1274
- Publisher
- American Society for Clinical Investigation
- DOI
- 10.1172/JCI113444
- PMID
- 3350973
- PMCID
- PMC329658
- ISSN
- 0021-9738
- eISSN
- 1558-8238
- Language
- English
- Date published
- 04/1988
- Academic Unit
- Molecular Physiology and Biophysics; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine
- Record Identifier
- 9984025452402771
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