Vasodilatory Effect of Pulsatile Pressure on Coronary Resistance Vessels

Goto, Masami; VanBavel, Ed; Giezeman, M. J. M. M.; Spaan, Jos A. E.

doi:10.1161/01.res.79.5.1039

Cited by 44 publications

(38 citation statements)

References 16 publications

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“…In our studies, incubating the segments at 50 mm Hg, the application of a preliminary conditioning pressure cycle of up to 150 mm Hg, applying a continuous pressure change at a rate of about 0.5 mm Hg/s instead of sudden step-like increases, mostly prevented the appearance of the stretch response during recorded cycles. The validity of our approach to measure the elastic properties in spontaneous contraction after the application of mechanical conditioning is supported by recent observations of Goto et al [41]. They found that pulsatile pressure cycles supposed to mimic in vivo changes in transmural pressure load in intramyocardial arterioles have a relaxing (i.e.…”

Section: Discussionsupporting

confidence: 67%

Segmental Differences in Geometric, Elastic and Contractile Characteristics of Small Intramural Coronary Arteries of the Rat

et al. 1998

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The depedence of elastic and contractile properties on the caliber of small intramural coronary arteries was investigated in the rat in vitro. Different segments of the left anterior descending coronary artery branching system were prepared for microarteriography. The segments were cannulated at both ends, immersed in oxygenated normal Krebs Ringer (nKR) solution. Intraluminal pressure was changed at a rate of about 0.5 mm Hg/s between 0 and 150 mm Hg in repeated cycles. The outer diameter was continuously measured with microangiometry. Pressure-diameter curves were recorded after preconditioning pressure cycles in nKR, with PGF_2α in the bath (7.5 × 10^–6 M), and in maximal relaxation with papaverine (2.8 × 10^–4 M). Biomechanical parameters were computed for vessels grouped according to their calibers (inner diameters: 50–150, 150–250, 250–350, >350 µm). Distensibility and contractility decreased with increasing caliber of the vessels, while the elastic modulus increased. Spontaneous tone was (at 100 mm Hg in mechanically preconditioned vessels) 18.8 ± 4.5, 8.4 ± 4.4, 9.7 ± 3.7 and 8.3 ± 3.8% in the four groups, respectively. PGF_2α contraction was maximal around the 300-µm caliber. Our study is the first direct demonstration that intramural small coronary arteries exhibit characteristic variability in their elastic and contractile properties as a function of their caliber. Such differences may be important in segmentally specific control processes of the coronary microcirculation.

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Section: Discussionsupporting

confidence: 67%

Segmental Differences in Geometric, Elastic and Contractile Characteristics of Small Intramural Coronary Arteries of the Rat

et al. 1998

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“…In addition, pulsatile change in transmural pressure may be involved in the autoregulation of flow, especially in some tissues such as myocardium. 14 On the other hand, chronically altered mechanical forces usually induce adaptive alterations of vessel wall shape and composition, which is termed vascular remodeling. [15][16][17] It has been shown that acute and transient high intraluminal pressure cause endothelial dysfunction and impaired endothelium-dependent vascular dilation.…”

Section: Discussionmentioning

confidence: 99%

High Intravascular Pressure Attenuates Vascular Dilation Responses of Small Mesenteric Arteries in the Rat

Gündüz

Meiselman

Başkurt

2008

Circ J

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revious studies have demonstrated that hypertension and cardiovascular diseases are associated with functional and morphological changes in arteries. [1][2][3] In hypertension, the small arteries and arterioles that determine peripheral resistance undergo changes such as increased reactivity to contractile agents, impaired endothelial function, and vascular smooth muscle growth. 4,5 Although it is unclear whether these are primary or secondary abnormalities, it is plausible that the increased intravascular pressure itself has some deleterious effect on vascular functional and/or morphological properties, and it has been proposed that such functional and morphological changes in arteries could be prevented by normalizing intravascular pressure. 6 Thus, independent of origin, high intravascular pressure can directly induce structural and functional modifications of the arterial wall.Blood vessels are continuously exposed to biomechanical forces, such as consist of shear stress induced by the movement of blood through the vessel lumen and stretch determined by luminal pressure and compliance. Chronic alterations in these forces could be important in vascular remodeling induced by both physiological (ie, exercise training) and pathological (ie, hypertension) conditions. 7 However, the variations in these mechanical forces can occur acutely and transiently in vivo. It is well documented that stretching of the arterial wall by increased transmural pressure alters the mechanical properties of vessels, as well as triggering various intracellular signaling pathways. [8][9][10] Thus it is possible that the vascular responsiveness of arteries also changes under conditions of high intraluminal pressure.However, to our knowledge, the vascular responses of vessels from normotensive subjects under high intraluminal pressure conditions have not yet been investigated. Rather, in previous studies, vascular responses to shear stress or agonists have been assessed at basal intraluminal pressures after a defined period of high intraluminal pressure. 11,12 Those myography studies using pre-pressurized vessels from normotensive subjects have demonstrated that endothelium-dependent dilation responses are directly attenuated by transient elevations in intravascular pressure, 11,12 while endothelium-independent vasorelaxation was found to be unaffected. 12 Because the vessel responses were examined after decreasing pressure to the original basal conditions, the mechanical effect of sustained high intravascular pressure on the vascular responses was not explored. Thus, the aim of this study was to investigate the vascular dilation responses of small mesenteric arteries (SMA) in rats at high intra-arterial pressure conditions. For this purpose, we examined the endothelium-dependent and -independent dilation responses under 3 different intravascular pressure conditions (ie, 50, 80 and 120 mmHg) using a pressure myography method. Methods AnimalsThirty adult male Wistar rats, 14 weeks old and weighing 300-320 g, were used in the present study...

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“…Larger pulse pressures (over 40 mm Hg) result in the dilatation of large and small arteries via an endothelium-independent mechanism [130], observations which can be attributed to the well-known plastic properties of the vascular wall, i.e. above a critical distension the cross-links formed between contractile filaments are disrupted and the vessel diameter increases passively [131].…”

Section: Response To Shear Stress and Pulsatile Stretch In Intact Vasmentioning

confidence: 99%

Pulsatile Stretch and Shear Stress: Physical Stimuli Determining the Production of Endothelium-Derived Relaxing Factors

Busse

Fleming²

1998

J Vasc Res

227

156

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Mechanical forces generated at the endothelium by fluid shear stress and pulsatile stretch are important in ensuring the continuous release of vasoactive endothelial autacoids. Although the mechanism by which endothelial cells are able to detect and convert these physical stimuli into chemical signals is unclear, this process involves the activation of integrins, G proteins and cascades of protein kinases. The constitutive endothelial nitric oxide synthase (NOS III), classified as a Ca²⁺/calmodulin-dependent isoform, can be activated by shear stress and isometric contraction in the absence of a maintained increase in [Ca²⁺]_i via a mechanism involving its redistribution within the cytoskeleton/caveolae and the activation of one or more regulatory NOS-associated proteins. Thus it would appear that the intracellular cascades activated by Ca²⁺-elevating receptor-dependent agonists, such as bradykinin, and hemodynamic stimuli are distinct. Rhythmic vessel distension is also able to elicit the synthesis of superoxide anions and the endothelium-derived hyperpolarizing factor which play a role in modulating arterial compliance in certain vascular beds.

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Vasodilatory Effect of Pulsatile Pressure on Coronary Resistance Vessels

Cited by 44 publications

References 16 publications

Segmental Differences in Geometric, Elastic and Contractile Characteristics of Small Intramural Coronary Arteries of the Rat

Segmental Differences in Geometric, Elastic and Contractile Characteristics of Small Intramural Coronary Arteries of the Rat

High Intravascular Pressure Attenuates Vascular Dilation Responses of Small Mesenteric Arteries in the Rat

Pulsatile Stretch and Shear Stress: Physical Stimuli Determining the Production of Endothelium-Derived Relaxing Factors

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