The role of active muscle vasodilatation in the alerting stage of the defence reaction

Abrahams, V. C.; Hilton, S. M.; Zbrożyna, A. W.

doi:10.1113/jphysiol.1964.sp007371

Cited by 171 publications

(48 citation statements)

References 10 publications

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“…Neurally mediated dilation is attractive because it might explain the immediate rise in flow with exercise and, in the case of motor nerves, the matching of blood flow and contractile activity. In many species either behavioral stimuli in conscious animals or electrical stimulation of selected brain areas in anesthetized preparations can evoke a "defense reaction" (1,96,159,213,307,308). This is a feed-forward adaptation that includes a rise in heart rate and blood pressure along with an increase in skeletal muscle blood flow that might "prepare" the animal for fight or flight.…”

Section: E Rapid Neurally Mediated Vasodilationmentioning

confidence: 99%

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Joyner

Casey

2015

Physiological Reviews

581

513

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LJoyner MJ, Casey DP. Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs. Physiol Rev 95: 549 -601, 2015; doi:10.1152/physrev.00035.2013.-This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans.

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Section: E Rapid Neurally Mediated Vasodilationmentioning

confidence: 99%

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Joyner

Casey

2015

Physiological Reviews

581

513

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“…In particular, it is possible that central command could activate sympathetic activity to some regions, e.g., skin, kidney, and gut, while inhibiting sympathetic activity to skeletal muscle. It is known that the defense reaction, another pattern of central neural activation, can produce qualitatively different effects on regional sympathetic outflows (Eliasson et al, 1951;Abrahams et al, 1964).…”

Section: Limitations Of the Studymentioning

confidence: 99%

Microneurographic studies of the mechanisms of sympathetic nerve responses to static exercise in humans.

Mark¹,

Victor²,

Nerhed³

et al. 1985

Circulation Research

661

505

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SUMMARY. The purpose of this study was to determine the contribution of muscle afferents and central command in regulating sympathetic nerve activity during static exercise in humans. In 20 healthy subjects, we recorded heart rate, arterial pressure, and efferent sympathetic nerve activity in the leg during arm exercise. Microelectrodes were inserted percutaneously into a fascicle of the peroneal nerve to measure sympathetic discharge to muscle. Measurements were obtained in nine subjects during sustained handgrip (30% maximal voluntary contraction) followed by relaxation or by arrested circulation of the forearm. Heart rate and arterial pressure increased during the first and second minutes of handgrip. Muscle sympathetic nerve activity increased from 261 ± 46 to 504 ± 97 units (mean ± SE; units = burst frequency x amplitude; P < 0.05) during the second minute of handgrip. During forearm ischemia following handgrip, heart rate returned promptly to control, whereas arterial pressure and muscle sympathetic nerve activity (631 ±115 units) remained elevated. In contrast, muscle sympathetic nerve activity returned toward control during relaxation without arrested circulation. These data indicate that muscle sympathetic nerve activity is increased by stimulation of chemically sensitive muscle afferents. To determine the influence of central command on muscle sympathetic nerve activity, we compared responses during ar. involuntary and a voluntary biceps contraction, each at 20% maximal voluntary contraction. Both maneuvers raised arterial pressure, but heart rate increased only during voluntary contraction. More importantly, muscle sympathetic nerve activity rose during involuntary contraction, but fell during voluntary effort. These studies demonstrate that during sustained handgrip in humans, stimulation of chemically sensitive muscle afferents increases muscle sympathetic nerve activity in the leg, and central command causes tachycardia, but inhibits muscle sympathetic outflow in the leg. (Circ Res 57: 461-469, 1985)

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“…They can be activated when a localized area in the hypothalamus and the midbrain periaqueductal grey matter, referred to as the defence area, is stimulated. During such stimulation sympathetic cholinergic vasodilatation in muscle is evoked along with vasoconstriction in the kidney and skin with increases in heart rate, cardiac output, arterial blood pressure and respiration (Eliasson, Folkow, Lindgren & Uvnas, 1951;Uvnas, 1954;Abrahams, Hilton & Zbrozyna, 1960, 1964Bolme, Ngai, Uvniis & Wallenberg, 1967;Hilton, Marshall & Timms, 1983;Bandler, Carrive & Zhang, 1991).…”

mentioning

confidence: 99%

Direct observations of sympathetic cholinergic vasodilatation of skeletal muscle small arteries in the cat.

Matsukawa

Shindo

Shirai

et al. 1997

The Journal of Physiology

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1. The aim of this study was to examine the actual changes of the internal diameter (i.d.) of arterial vessels of skeletal muscle evoked by activation of sympathetic cholinergic nerve fibres during stimulation of the hypothalamic defence area in anaesthetized cats. 2. For this purpose, we have used our novel X-ray TV system for visualizing small arteries (100-500,m i.d.) of the triceps surae muscle and larger extramuscular arteries (500-1400 ,m i.d.) of the hindlimb (the femoral (FA), popliteal (PA) and distal caudal femoral (DCFA) arteries). The passage of a contrast medium from the large extramuscular arteries to the smaller intramuscular arteries was serially measured before and during hypothalamic stimulation. 3. Hypothalamic stimulation increased mean arterial blood pressure, heart rate and femoral vascular conductance. The i.d. of FA, PA, and DCFA did not change during the hypothalamic stimulation, whereas the i.d. of small arteries in the triceps surae muscle increased by 48 + 2% (mean + S.E.M.) and the cross-sectional area increased concomitantly by 118%.The maximum increase in i.d. of 78 + 6%, was observed in arteries of 100-200 ,m. These increases in diameter were markedly reduced by intra-arterial injection of atropine or by cutting the sciatic nerve, but not by phentolamine and propranolol given together. 4. The vasodilatation evoked by hypothalamic stimulation was seen in almost all the sections of the small arteries observed under control conditions and was distributed along the entire length of the vessel. In addition, the number of arterial vessels that could be detected increased by 42% during hypothalamic stimulation. The newly detected arterial branches, which ranged from 100 to 300 ,tm in diameter, mostly arose from the branching points. 5. It is concluded that stimulation of sympathetic cholinergic nerve fibres dilates the small arteries of skeletal muscle ranging from 100 to 500/,m, but not the larger extramuscular arteries.

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The role of active muscle vasodilatation in the alerting stage of the defence reaction

Cited by 171 publications

References 10 publications

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Microneurographic studies of the mechanisms of sympathetic nerve responses to static exercise in humans.

Direct observations of sympathetic cholinergic vasodilatation of skeletal muscle small arteries in the cat.

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