Journal article
Mechanics of Cerebral Arterioles in Hypertensive Rats
Circulation research, Vol.62(1), pp.56-64
01/1988
DOI: 10.1161/01.RES.62.1.56
PMID: 3335057
Abstract
Chronic hypertension is associated with hypertrophy of cerebral blood vessels. Previous studies of the mechanical properties of cerebral vessels in chronic hypertension have examined large cerebral arteries. The goals of this study were first to develop a method to examine vascular mechanics of cerebral arterioles in vivo and second to determine whether the stiffness of cerebral arterioles is altered hi the presence of chronic hypertension. We calculated circumferential stress and strain of pial arterioles in age-matched, anesthetized stroke-prone spontaneously hypertensive rats (SHRSP) and hi Wistar Kyoto rats (WKY) from measurements of pial arteriolar pressure, inner diameter, and wall thickness. Pial arteriolar pressure was measured with a servonull system. Smooth muscle of pial arterioles was deactivated with ethylenediaminetetraacetic acid (EDTA), and pressure-diameter relations were examined during step-wise reductions in pressure. Prior to deactivation of smooth muscle in 3-4-month-old rats, pial arteriolar pressure was greater in SHRSP than in WKY (110 ±4 versus 75 ±2 mm Hg [mean±SE]; p < 0.05). Pial arteriolar diameter, which was measured at prevailing levels of pial arteriolar pressure, was less hi SHRSP than hi WKY (52 ± 5 versus 63 ± 3 μm; p < 0.05). Following deactivation of smooth muscle, diameter of pial arterioles at 70 mm Hg of pial arteriolar pressure was similar hi the two groups104 ±6 μm in SHRSP and 109 ±3 μm in WKY (p > 0.05). Wall thickness was 4.5 ±0.2 μm in SHRSP and 4.1 ±0.1 μm in WKY (p > 0.05). The stress-strain relation hi deactivated pial arterioles was shifted to the right hi SHRSP, which indicates that circumferential stiffness of pial arterioles is decreased in young SHRSP. To determine whether hypertrophy of pial arterioles, which occurs with maturation, is associated with increases in arteriolar stiffness, we examined stress-strain characteristics in 6-8-month-old SHRSP and WKY. In older rats, diameter of both active and deactivated pial arterioles was less in SHRSP than hi WKY. Wall thickness was significantly greater in SHRSP than in WKY (5.8 ±0.5 versus 3.8 ±0.2 μm; p < 0.05). The stress-strain relation, however, was shifted even further to the right in 6-8-month-old SHRSP with respect to WKY. We conclude that the stiffness of cerebral arterioles is decreased hi SHRSP with established hypertension despite pronounced vascular hypertrophy.
Details
- Title: Subtitle
- Mechanics of Cerebral Arterioles in Hypertensive Rats
- Creators
- Gary Baumbach - From the University of Iowa College of Medicine, Departments of Pathology and Internal Medicine, Cardiovascular Center, and the VA Medical Center, Iowa City, Iowa; the Department of Surgery (P.B.D.), Hines Veterans Administration Hospital, and Loyola University Medical Center, Hines, IIIPhilip DobrinMichael HartDonald Heistad
- Resource Type
- Journal article
- Publication Details
- Circulation research, Vol.62(1), pp.56-64
- DOI
- 10.1161/01.RES.62.1.56
- PMID
- 3335057
- NLM abbreviation
- Circ Res
- ISSN
- 0009-7330
- eISSN
- 1524-4571
- Publisher
- American Heart Association, Inc
- Language
- English
- Date published
- 01/1988
- Academic Unit
- Pathology; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984040553302771
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