Remote arteriolar dilations in response  to muscle contraction under capillaries

Cohen, Kenneth D.; Berg, B. R.; Sarelius, Ingrid H.

doi:10.1152/ajpheart.2000.278.6.h1916

Cited by 64 publications

(96 citation statements)

References 27 publications

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“…Recent evidence indicates that one mechanism responsible for this metabolically induced precapillary vasodilatation is via the endothelial cells [30]. In the light of this evidence, we postulated that endothelial dysfunction might interfere with this pathway, thereby giving rise to a progressive decrease in nutritive flow as the severity of the disease increases.…”

Section: Discussionmentioning

confidence: 92%

Resting peripheral blood flow in normal pregnancy and in pre-eclampsia

ANIM-NYAME¹,

SOORANNA²,

JOHNSON³

et al. 2000

Clinical Science

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Multiple organ dysfunction followed by end organ failure occurs in pre-eclampsia. While one would intuitively reason that one of the factors contributing to the end organ failure is poor nutritional blood flow, this has yet to be demonstrated. The aim of the present study was to determine whether changes in resting nutritional blood flow occur in pre-eclampsia. We used strain-gauge plethysmography to study calf blood flow in 19 women with pre-eclampsia, 13 normal pregnant women and 17 non-pregnant controls. We reasoned that, since the calf comprises mostly skeletal muscle, without anastomotic channels, blood flowing through this region would primarily reflect nutritive flow. Calf blood flow was significantly reduced in women with pre-eclampsia (1.95+/-0.9 ml.min(-1).100 ml(-1)) compared with normal pregnant (3.9+/-1.4 ml.min(-1).100 ml(-1)) and non-pregnant (3.8+/-1.0 ml.min(-1).100 ml(-1)) women (P=0.0004 and P=0.0005 respectively; ANOVA). Blood flow in pre-eclampsia was also correlated significantly with platelet count as an index of disease severity. In addition, there was a significant negative correlation between blood flow and systolic blood pressure (r=-0.69, P=0.004) in the women with pre-eclampsia. These findings support the hypothesis that nutritional blood flow is reduced in pre-eclampsia. We suggest that measurement of resting calf blood flow could give a non-invasive index of deterioration of nutritive blood flow to vital organs in pre-eclampsia.

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Section: Discussionmentioning

confidence: 92%

Resting peripheral blood flow in normal pregnancy and in pre-eclampsia

ANIM-NYAME¹,

SOORANNA²,

JOHNSON³

et al. 2000

Clinical Science

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“…This mechanism is important for coordination of flow as it allows vasodilatation to occur in the larger upstream vessels that do not necessarily experience the chemical or mechanical stimuli that are present in proximity of the working muscle fibers. It has been clearly demonstrated that contraction of muscle fibers induces conducted vasodilation in animal models, supporting a functional role of this mechanism in the exercising skeletal muscle (67,305).…”

Section: Control Of Exercise Hyperemiamentioning

confidence: 83%

Cardiovascular Adaptations to Exercise Training

Hellsten

Nyberg

2015

Comprehensive Physiology

206

185

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Aerobic exercise training leads to cardiovascular changes that markedly increase aerobic power and lead to improved endurance performance. The functionally most important adaptation is the improvement in maximal cardiac output which is the result of an enlargement in cardiac dimension, improved contractility, and an increase in blood volume, allowing for greater filling of the ventricles and a consequent larger stroke volume. In parallel with the greater maximal cardiac output, the perfusion capacity of the muscle is increased, permitting for greater oxygen delivery. To accommodate the higher aerobic demands and perfusion levels, arteries, arterioles, and capillaries adapt in structure and number. The diameters of the larger conduit and resistance arteries are increased minimizing resistance to flow as the cardiac output is distributed in the body and the wall thickness of the conduit and resistance arteries is reduced, a factor contributing to increased arterial compliance. Endurance training may also induce alterations in the vasodilator capacity, although such adaptations are more pronounced in individuals with reduced vascular function. The microvascular net increases in size within the muscle allowing for an improved capacity for oxygen extraction by the muscle through a greater area for diffusion, a shorter diffusion distance, and a longer mean transit time for the erythrocyte to pass through the smallest blood vessels. The present article addresses the effect of endurance training on systemic and peripheral cardiovascular adaptations with a focus on humans, but also covers animal data.

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“…Signals such as changes of membrane potential spread along endothelial and/or vascular smooth muscle cells, thereby enabling the arteriole to react as a single unit leading to constriction or dilation over a long distance (9-11, 23, 30). Such a mechanism is presumably involved in the control of functional hyperemia, as dilation of upstream arterioles in response to contraction of skeletal muscle fibers was attenuated after blockade of gap junctions (6).…”

mentioning

confidence: 99%

Lack of vascular connexin 40 is associated with hypertension and irregular arteriolar vasomotion

Wit

Roos

Bolz

et al. 2003

Physiological Genomics

184

154

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Gap-junctional communication coordinates the behavior of individual cells in arterioles. Gap junctions are formed by connexins 40 (Cx40), Cx43, Cx37, and Cx45 in the vasculature. Previously, we have shown that lack of Cx40 impairs conduction of dilatory signals along arterioles. Herein, we examined whether hypertension is present in conscious animals and whether this is a direct effect or due to secondary mechanisms. Mean arterial pressure was elevated by 20–25 mmHg in conscious Cx40-deficient mice (Cx40−/−) compared with wild-type controls in both sexes. Differences in heart rate were not observed. Blockade of NO synthase increased pressure equally in both genotypes. Conversely, the angiotensin AT1-receptor antagonist, candesartan, decreased pressure to similar extents in Cx40−/− and wild-type mice. Acetylcholine and sodium nitroprusside (0.05–15 nmol) were equally potent and effective in decreasing pressure and inducing dilatory responses in the microcirculation. However, in contrast to wild type, Cx40−/− arterioles exhibited spontaneous, irregular vasomotion leading temporarily to complete vessel closure. We conclude that loss of Cx40 is associated with hypertension independent of the action of angiotensin II. It is also not related to an altered efficacy of NO or other endothelial dilators. However, the observed irregular vasomotion suggests that peripheral vascular resistance is affected.

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Remote arteriolar dilations in response to muscle contraction under capillaries

Cited by 64 publications

References 27 publications

Resting peripheral blood flow in normal pregnancy and in pre-eclampsia

Resting peripheral blood flow in normal pregnancy and in pre-eclampsia

Cardiovascular Adaptations to Exercise Training

Lack of vascular connexin 40 is associated with hypertension and irregular arteriolar vasomotion

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