Vascular Responsiveness in the Unstressed Borderline Hypertensive Rat
| Autor: | D. B. Stratton, R. J. Morrow, B. J. Sanders |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
Serotonin medicine.medical_specialty Endothelium Physiology Hemodynamics Aorta Thoracic Blood Pressure Isometric exercise Rats Inbred WKY Muscle Smooth Vascular Contractility Phenylephrine Isometric Contraction Rats Inbred SHR medicine.artery Internal medicine Internal Medicine medicine Animals Thoracic aorta Aorta Dose-Response Relationship Drug business.industry General Medicine Acetylcholine Rats Endocrinology medicine.anatomical_structure Anesthesia cardiovascular system Endothelium Vascular business medicine.drug |
| Zdroj: | Clinical and Experimental Hypertension. 16:105-117 |
| ISSN: | 1525-6006 1064-1963 |
| DOI: | 10.3109/10641969409068588 |
| Popis: | This study compares vascular responses of unstressed borderline hypertensive rats (BHR) to age-matched Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Rings of thoracic aorta were mounted for isometric force determinations in tissue baths. Cumulative additions of phenylephrine (PE) or serotonin (5-HT) produced contractile responses in BHR aorta that were less than WKY but greater than SHR. Removing the endothelium increased force development to both agonists, with BHR showing the greatest increase. Based on EC50 determinations, no differences in PE sensitivity existed between groups, although in response to 5-HT, rings from SHR were significantly more sensitive than WKY. While the sensitivity of all rings increased with denuding, BHR showed a greater relative increase in sensitivity than WKY or SHR (intact EC50 divided by denuded EC50) to both PE and 5-HT. This suggests that there may be greater endothelium-derived relaxation in BHR than in WKY or SHR. In rings precontracted with 1 microM PE, the cumulative addition of acetylcholine resulted in greater relaxation in BHR than in SHR and WKY preparations. Thus, rings from unstressed BHR, which have only slightly higher blood pressures than WKY rats, demonstrate greater endothelium-mediated relaxation than WKY or SHR. Increased endothelium-derived relaxation may represent a possible mechanism for masking hypertension in BHR that is compromised as a result of exposure to a chronic stress paradigm. |
| Databáze: | OpenAIRE |
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