Journal article
Mechanisms of impaired endothelium-dependent cerebral vasodilatation in response to bradykinin in hypertensive rats
Stroke (1970), Vol.22(9), pp.1177-1182
1991
DOI: 10.1161/01.STR.22.9.1177
PMID: 1926261
Abstract
Bradykinin produces less dilatation of pial arterioles in stroke-prone spontaneously hypertensive rats than in normotensive Wistar-Kyoto rats. The goals of this study were to determine the mediator of bradykinin-induced dilatation in cerebral arterioles of rats and to determine whether responses to this mediator are altered in hypertensive rats. Diameter of pial arterioles (20-65 microns) was measured using intravital microscopy in 18 normotensive and 17 hypertensive rats. Superfusion of 3 x 10(-7) M bradykinin dilated pial arterioles by 53 +/- 4% (mean +/- SEM) in normotensive rats but only 33 +/- 6% in hypertensive rats (p less than 0.05 versus normotensive rats). Vasodilatation in response to bradykinin was almost completely inhibited by 280 units/ml catalase in both normotensive and hypertensive rats (n = 7 and n = 7, respectively) whereas 150 units/ml superoxide dismutase (n = 6 and n = 5, respectively) and 1 mM deferoxamine (n = 5 and n = 5, respectively) did not attenuate bradykinin-induced vasodilatation. These findings suggest that hydrogen peroxide is the mediator of bradykinin-induced dilatation in cerebral arterioles of rats. We also examined responses of cerebral arterioles to hydrogen peroxide in five normotensive and six hypertensive rats. Dilator responses of cerebral arterioles to 3.2 x 10(-5) M to 1.6 x 10(-4) M hydrogen peroxide did not differ in normotensive and hypertensive rats, which suggests that impaired dilatation of cerebral arterioles in response to bradykinin is not related to altered responsiveness of smooth muscle to an endothelium-derived relaxing factor.
Details
- Title: Subtitle
- Mechanisms of impaired endothelium-dependent cerebral vasodilatation in response to bradykinin in hypertensive rats
- Creators
- Shuh-Tsong Yang - Univ. Iowa coll. medicine, cadiovascular cent., dep. pharmacology, Iowa City IA, United StatesW. G MAYAHAN - Univ. Iowa coll. medicine, cadiovascular cent., dep. pharmacology, Iowa City IA, United StatesF. M FARACI - Univ. Iowa coll. medicine, cadiovascular cent., dep. pharmacology, Iowa City IA, United StatesD. D HEISTAD - Univ. Iowa coll. medicine, cadiovascular cent., dep. pharmacology, Iowa City IA, United States
- Resource Type
- Journal article
- Publication Details
- Stroke (1970), Vol.22(9), pp.1177-1182
- Publisher
- Lippincott Williams & Wilkins; Hagerstown, MD
- DOI
- 10.1161/01.STR.22.9.1177
- PMID
- 1926261
- ISSN
- 0039-2499
- eISSN
- 1524-4628
- Language
- English
- Date published
- 1991
- Academic Unit
- Cardiovascular Medicine; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984040567302771
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