Journal article
Behavioral stress alters coronary vascular reactivity in borderline hypertensive rats
Journal of hypertension, Vol.15(3), pp.301-307
03/1997
DOI: 10.1097/00004872-199715030-00012
PMID: 9468458
Abstract
BACKGROUNDBehavioral stress has been proposed to contribute to the occurrence of myocardial ischemia.
OBJECTIVETo investigate the effect of chronic exposure to behavioral stress on the function and structure of the coronary artery of borderline hypertensive rats (BHR).
DESIGNBHR were either exposed to an air-jet stress for 2 h/day for 10 days or kept in their cage for 10 days.
METHODSAfter 10 days, hemodynamic measurements in conscious animals were recorded, and their hearts were removed for isolation of a left ventricular coronary artery for functional studies or for fixation by retrograde perfusion for study with scanning electron microscopy. Vascular reactivity was measured in isolated coronary arteries (≈250 μm) maintained at an intraluminal diameter of 40 mmHg while the intraluminal diameter was recorded continuously.
RESULTSThe resting mean arterial pressure and heart rate in conscious, unrestrained BHR were not altered significantly by exposure to 10 days of 2 h/day air-jet stress. Coronary artery relaxation in response to the endothelium-dependent vasodilator acetylcholine was impaired in rats exposed to the air-jet stress compared with that in controls. An attenuated response to exogenous nitric oxide in coronary arteries from stressed BHR was confirmed by the finding of a reduced sensitivity to nitroprusside, which releases nitric oxide independently from the endothelium. However, relaxation of coronary arteries in response to isoproterenol, which acts independently from nitric oxide, was not altered. Coronary artery contraction in response to endothelin-1 and phenylephrine was not altered in vessels taken from BHR exposed to behavioral stress compared with that in vessels from control rats. Scanning electron microscopy of the endothelial surface of the septal coronary artery showed no difference between vessels from control and stressed BHR.
CONCLUSIONThese results indicate that behavioral stress impairs endothelium-dependent and nitric oxide-mediated coronary relaxation, but does not alter α1-adrenoceptor or endothelin-1-mediated contraction. By impairing coronary artery vascular relaxation, chronic exposure to behavioral stress may contribute to myocardial ischemia.
Details
- Title: Subtitle
- Behavioral stress alters coronary vascular reactivity in borderline hypertensive rats
- Creators
- Leslie Fuchs - 1Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912 2Department of Pathology, SUNY Health Science Center at Syracuse, Syracuse, NY 13202 3Departments of Pharmacology, Pathology, and Psychology and the Cardiovascular Center, University of Iowa, Iowa City, IA 52242, USASteve LandasAlan Johnson
- Resource Type
- Journal article
- Publication Details
- Journal of hypertension, Vol.15(3), pp.301-307
- Publisher
- Lippincott-Raven Publishers
- DOI
- 10.1097/00004872-199715030-00012
- PMID
- 9468458
- ISSN
- 0263-6352
- eISSN
- 1473-5598
- Language
- English
- Date published
- 03/1997
- Academic Unit
- Psychological and Brain Sciences; Neuroscience and Pharmacology; Health and Human Physiology
- Record Identifier
- 9984213419802771
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