Journal article
Differences in Direct Effects of Adrenergic Stimuli on Coronary, Cutaneous, and Muscular Vessels
The Journal of clinical investigation, Vol.51(2), pp.279-287
02/1972
DOI: 10.1172/JCI106812
PMID: 4400290
Abstract
Direct effects of adrenergic stimuli on coronary vessels in dogs were compared with effects on vessels to skin (hind paw) and skeletal muscle (gracilis muscle) after intravenous administration of practolol (2 mg/kg), a selective myocardial beta receptor blocker which minimized indirect effects of myocardial stimulation on coronary vascular resistance. The left circumflex coronary, cranial tibial, and gracilis arteries were perfused separately but simultaneously at constant flow. Perfusion pressures, left ventricular pressure and dP/dt. and heart rate were recorded. Changes in perfusion pressure to each bed reflected changes in vascular resistance.\nThe direct constrictor effects of sympathetic nerve stimulation, norepinephrine and phenylephrine on coronary vessels were minimal compared with effects on cutaneous and muscular vessels. Subsequent blockade of vascular beta receptors did not augment the constrictor responses. Angiotensin, a nonadrenergic stimulus, produced striking coronary vasoconstriction which exceeded that in skin and approximated that in muscle. These results suggests that there is a paucity of alpha adrenergic receptors in coronary vessels compared to cutaneous and muscular vessels.\nDirect dilator responses to isoproterenol were similar in coronary and cutaneous vessels, but were greater in muscular vessels. Responses to glyceryl trinitrate, a nonadrenergic dilator, also were greater in skeletal muscle. Therefore, differences in effects of isoproterenol on the three beds may reflect differences in reactivity to dilator stimuli rather than differences in the density of beta receptors.\nIn contrast to norepinephrine, the predominant direct effect of epinephrine on coronary vessels was dilatation mediated through activation of vascular beta receptors. A constrictor effect caused by stimulation of alpha receptors was unmasked by propranolol.\nFinally, the order of potency of agonists in stimulating coronary vascular beta receptors and the demonstration of selective beta receptor blockade with practolol suggest that beta receptors in coronary vessels resemble those in peripheral vessels more than those in myocardium.
Details
- Title: Subtitle
- Differences in Direct Effects of Adrenergic Stimuli on Coronary, Cutaneous, and Muscular Vessels
- Creators
- Allyn L Mark - Cardiovascular Division, Department of Internal Medicine, University of Iowa College of Medicine and The Veterans Administration Hospital, Iowa City, Iowa 52240Francois M Abboud - Cardiovascular Division, Department of Internal Medicine, University of Iowa College of Medicine and The Veterans Administration Hospital, Iowa City, Iowa 52240Phillip G Schmid - Cardiovascular Division, Department of Internal Medicine, University of Iowa College of Medicine and The Veterans Administration Hospital, Iowa City, Iowa 52240Donald D Heistad - Cardiovascular Division, Department of Internal Medicine, University of Iowa College of Medicine and The Veterans Administration Hospital, Iowa City, Iowa 52240Howard E Mayer - Cardiovascular Division, Department of Internal Medicine, University of Iowa College of Medicine and The Veterans Administration Hospital, Iowa City, Iowa 52240
- Resource Type
- Journal article
- Publication Details
- The Journal of clinical investigation, Vol.51(2), pp.279-287
- Publisher
- American Society for Clinical Investigation
- DOI
- 10.1172/JCI106812
- PMID
- 4400290
- ISSN
- 0021-9738
- eISSN
- 1558-8238
- Language
- English
- Date published
- 02/1972
- Academic Unit
- Molecular Physiology and Biophysics; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984025478802771
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