Journal article
Endothelium-Dependent Responses of Cerebral Blood Vessels During Chronic Hypertension
Hypertension (Dallas, Tex. 1979), Vol.17(5), pp.612-618
05/1991
DOI: 10.1161/01.HYP.17.5.612
PMID: 1902437
Abstract
Acetylcholine produces less dilatation of pial arterioles in stroke-prone spontaneously hypertensive rats (SHRSP) than in normotensive (WKY) rats. Responses of cerebral vessels to acetylcholine and bradykinin appear to involve different mechanisms. Our first goal was to determine whether responses of pial arterioles to bradykinin are impaired in SHRSP. Diameter of pial arterioles (20-60 /tm) was measured using intravital microscopy in WKY rats and SHRSP (9-12 months old). Superfusion of bradykinin (3xlO~7 M) dilated pial arterioles by 35±6% (mean±SEM) in WKY rats, but only 21±3% in SHRSP (p<0.05 versus WKY rats). Both nitric oxide (5 x 10~7 M) and nitroglycerin (10"′ M) produced similar vasodilatation in WKY rats and SHRSP. Our second goal was to determine whether alteration of postreceptor mechanisms contributes to impairment of endothelium-dependent cerebral vasodilatation in SHRSP. Calcium ionophore A23187 (10~5 M) produced more vasodilatation in WKY rats than in SHRSP (32±8% versus 9±4%, p<0.05). Responses to A23187 (10* M) were inhibited by indomethacin (46±13% versus 15±5%, p<0.05) in WKY rats, whereas responses to A23187 (10"′ M) were potentiated modestly by indomethacin (-3±2% versus 4±2%, p<0.05) in SHRSP. Thus, 1) chronic hypertension impairs responses to two distinct endotheliumdependent dilators in pial arterioles, 2) responses of pial arterioles to nitric oxide are not altered during chronic hypertension, 3) impairment of endothelium-dependent responses in chronic hypertension involves an alteration in postreceptor mechanisms, and 4) impaired responses to A23187 in chronic hypertension may be due in part to co-release of a constrictor substance through the cyclooxygenase pathway.
Details
- Title: Subtitle
- Endothelium-Dependent Responses of Cerebral Blood Vessels During Chronic Hypertension
- Creators
- Shuh-Tsong Yang - From the Departments of Pharmacology and Internal Medicine, Cardiovascular Center and Veterans Administration Medical Center, University of Iowa College of Medicine, Iowa City, IowaWilliam MayhanFrank FaraciDonald Heistad
- Resource Type
- Journal article
- Publication Details
- Hypertension (Dallas, Tex. 1979), Vol.17(5), pp.612-618
- DOI
- 10.1161/01.HYP.17.5.612
- PMID
- 1902437
- NLM abbreviation
- Hypertension
- ISSN
- 0194-911X
- eISSN
- 1524-4563
- Publisher
- American Heart Association, Inc
- Language
- English
- Date published
- 05/1991
- Academic Unit
- Cardiovascular Medicine; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984040573802771
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