Mechanical Properties of Rat Middle Cerebral Arteries With and Without Myogenic Tone
Author:
Coulson Rebecca J.1, Cipolla Marilyn J.2, Vitullo Lisa2, Chesler Naomi C.13
Affiliation:
1. Mechanical Engineering Department, University of Vermont, Burlington, VT 05405 2. Neurology Department, University of Vermont, Burlington, VT 05405 3. Biomedical Engineering Department, University of Wisconsin, Madison, WI 53706
Abstract
The inner diameter and wall thickness of rat middle cerebral arteries (MCAs) were measured in vitro in both a pressure-induced, myogenically-active state and a drug-induced, passive state to quantify active and passive mechanical behavior. Elasticity parameters from the literature (stiffness derived from an exponential pressure-diameter relationship, β, and elasticity in response to an increment in pressure, Einc-p) and a novel elasticity parameter in response to smooth muscle cell (SMC) activation, Einc-a, were calculated. β for all passive MCAs was 9.11±1.07 but could not be calculated for active vessels. The incremental stiffness increased significantly with pressure in passive vessels; Einc-p 106 dynes/cm2 increased from 5.6±0.5 at 75 mmHg to 14.7±2.4 at 125 mmHg, (p<0.05). In active vessels, Einc-p 106 dynes/cm2 remained relatively constant (5.5±2.4 at 75 mmHg and 6.2±1.0 at 125 mmHg). Einc-a 106 dynes/cm2 increased significantly with pressure (from 15.1±2.3 at 75 mmHg to 49.4±12.6 at 125 mmHg, p<0.001), indicating a greater contribution of SMC activity to vessel wall stiffness at higher pressures.
Publisher
ASME International
Subject
Physiology (medical),Biomedical Engineering
Reference31 articles.
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