Journal article
Vascular responses after alpha adrenergic receptor blockade
The Journal of clinical investigation, Vol.47(1), pp.10-19
01/01/1968
DOI: 10.1172/JCI105700
PMID: 16695932
Abstract
The effects of nerve stimulation and of intraarterial injections of norepinephrine on arterial and venous resistances were studied in the perfused forelimb of dog before and after administration of the alpha adrenergic receptor blocker phenoxybenzamine.Pressures were recorded from the perfused brachial artery and a small metacarpal vein in the forepaw. Blood flow to the whole forelimb was maintained constant. Changes in perfusion pressure in the brachial artery reflected primarily changes in arterial resistance and changes in small vein pressure reflected changes in resistance of venous segments downstream from the point of pressure measurement.Alpha receptor blockade reduced vasoconstrictor responses to both nerve stimulation and norepinephrine. Responses to angiotensin, used in these experiments as an internal control, were not blocked consistently in a dose-related manner indicating that the effects of phenoxybenzamine were specific to adrenergic stimuli.Increases in venous pressure in response to norepinephrine and to nerve stimulation were blocked almost completely whereas increases in arterial pressure were reduced only in part by the blocker. The more effective reduction of pressor responses in the small vein was not caused by a passive reduction in blood flow through the paw nor was it caused by a reduction in the concentration of norepinephrine in the venous effluent reaching the venous segments.This differential effect of alpha receptor blockade on increases in venous and arterial resistances may account for the beneficial effect of phenoxybenzamine in shock.
Details
- Title: Subtitle
- Vascular responses after alpha adrenergic receptor blockade
- Creators
- Francois M AbboudJohn W Eckstein
- Resource Type
- Journal article
- Publication Details
- The Journal of clinical investigation, Vol.47(1), pp.10-19
- Publisher
- American Society for Clinical Investigation
- DOI
- 10.1172/JCI105700
- PMID
- 16695932
- ISSN
- 0021-9738
- eISSN
- 1558-8238
- Language
- English
- Date published
- 01/01/1968
- Academic Unit
- Molecular Physiology and Biophysics; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine
- Record Identifier
- 9984025465202771
Metrics
22 Record Views