title: Effects of longitudinal stretch on VSM tone and distensibility of muscular conduit arteries.
abstract: With progressing age, large arteries diminish their longitudinal stretch, which in extreme cases results in tortuosity. Increased age is also associated with loss of vessel distensibility. We measured pressure-diameter curves from muscular porcine carotid arteries ex vivo at different longitudinal stretch ratios (lambda(z) = 1.4 and 1.8) and under different vascular smooth muscle (VSM) conditions (fully relaxed, normal VSM tone, and maximally contracted). Distensibility was found to be halved by decreasing longitudinal stretch from lambda(z) = 1.8 to 1.4 at physiological pressures. This counterintuitive observation is possible because highly nonlinear elastic modulus of the artery and anisotropic properties. Furthermore, a significantly larger basal VSM contraction was observed at lambda(z) = 1.8 than 1.4, although this was clearly not related to a myogenic response during inflation. This dependence of VSM tone to longitudinal stretch may have possible implications on the functional characteristics of the arterial wall.
authors.affiliation: Laboratory of Hemodynamics and Cardiovascular Technologies, Swiss Federal Institute of Technology, 1015 Lausanne, Switzerland. martin.zulliger@epfl.ch
authors.forename: Martin A
authors.initials: MA
authors.lastname: Zulliger
authors.forename: Naomi T M R
authors.initials: NT
authors.lastname: Kwak
authors.forename: Theodora
authors.initials: T
authors.lastname: Tsapikouni
authors.forename: Nikos
authors.initials: N
authors.lastname: Stergiopulos
mesh_terms: D000818:Animals; D016880:Anisotropy; D001696:Biomechanical Phenomena; D001794:Blood Pressure / Q000502:physiology; D002339:Carotid Arteries / Q000502:physiology*; D004548:Elasticity; D066298:In Vitro Techniques; D008955:Models, Cardiovascular; D009129:Muscle Tonus / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D013314:Stress, Mechanical; D013552:Swine; D014654:Vascular Patency / Q000502:physiology