Skeletal Muscle Vasculature and Systemic Hypoxia

Physiology ◽  
1995 ◽  
Vol 10 (6) ◽  
pp. 274-280
Author(s):  
JM Marshall
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Intravital Microscopy ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Nerve Activity ◽  
Systemic Hypoxia

Studies involving recordings of gross muscle blood flow and intravital microscopy have been used to analyze the behavior of muscle vasculature during systemic hypoxia. The roles of sympathetic nerve activity, circulating hormones (e.g., catecholamines, angiotensin, vasopressin), and locally released adenosine and K+ in determining the behavior of arterial and venous vessels are considered.

Neural control of muscle blood flow during exercise

2004 ◽  
Vol 97 (2) ◽  
pp. 731-738 ◽  
Author(s):  
Gail D. Thomas ◽  
Steven S. Segal
Keyword(s):  
Blood Pressure ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Sympathetic Nerve ◽  
Neural Control ◽  
Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Nerve Activity ◽  
Arterial Blood

Activation of skeletal muscle fibers by somatic nerves results in vasodilation and functional hyperemia. Sympathetic nerve activity is integral to vasoconstriction and the maintenance of arterial blood pressure. Thus the interaction between somatic and sympathetic neuroeffector pathways underlies blood flow control to skeletal muscle during exercise. Muscle blood flow increases in proportion to the intensity of activity despite concomitant increases in sympathetic neural discharge to the active muscles, indicating a reduced responsiveness to sympathetic activation. However, increased sympathetic nerve activity can restrict blood flow to active muscles to maintain arterial blood pressure. In this brief review, we highlight recent advances in our understanding of the neural control of the circulation in exercising muscle by focusing on two main topics: 1) the role of motor unit recruitment and muscle fiber activation in generating vasodilator signals and 2) the nature of interaction between sympathetic vasoconstriction and functional vasodilation that occurs throughout the resistance network. Understanding how these control systems interact to govern muscle blood flow during exercise leads to a clear set of specific aims for future research.

scholarly journals Attenuation of rapid onset vasodilation with advanced age : roles of adrenergic and endothelial signaling

2016 ◽  
Author(s):  
◽  
Shenghua Yuan Sinkler
Keyword(s):  
Physical Activity ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Rapid Onset ◽  
Nerve Activity ◽  
Endothelium Dysfunction ◽  
Effects Of Aging

Rapid onset vasodilation (ROV) occurs immediately in response to skeletal muscle contraction and initiates a prompt increase in blood flow and oxygen delivery that facilitate the transition to exercise. Muscle blood flow is attenuated during aging which limits physical activity. Understanding the mechanisms that attenuate ROV requires invasive measurements that cannot be performed in human subjects. Published studies indicate that the effects of aging on muscle blood flow are similar in mice and in humans. Using our established mouse model to study the actual blood vessels that control blood flow in living skeletal muscle, the focus of my research is to understand where and how aging affects ROV in light of enhanced sympathetic nerve activity and endothelium dysfunction. A mouse was anesthetized and a skeletal muscle was prepared for studying individual microvessels using a microscope. The muscle was stimulated to contract with the amount and speed of vessel opening (vasodilation) recorded. I used selective interventions to modulate sympathetic or endothelial function and compared ROV for each vessel branch between Young (4 months) and Old (24 months) mice to resolve the effects of aging. I found that sympathetic activation attenuates ROV and that endothelium is integral to ROV. Thus, enhanced sympathetic nerve activity and endothelium dysfunction with aging attenuates ROV. These effects are greater effects in larger upstream vessels, which can restrict blood flow into active muscles. My research provides new insight for improving muscle blood flow, thereby promoting physical activity to improve the quality of life for aging individuals.

scholarly journals Impact of gender on benefits of exercise training on sympathetic nerve activity and muscle blood flow in heart failure

2009 ◽  
Vol 12 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Ligia M. Antunes-Correa ◽  
Ruth C. Melo ◽  
Thais S. Nobre ◽  
Linda M. Ueno ◽  
Fabio G.M. Franco ◽  
...  
Keyword(s):  
Heart Failure ◽  
Blood Flow ◽  
Exercise Training ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Nerve Activity

scholarly journals Sesame lignans increase sympathetic nerve activity and blood flow in rat skeletal muscles

2020 ◽  
pp. 253-260
Author(s):  
K. Egawa ◽  
Y. Horii ◽  
Y. Misonou ◽  
I. Yamasaki ◽  
D. Takemoto ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Autonomic Nerves ◽  
Nerve Activity ◽  
Beneficial Effects ◽  
Antioxidative Effects ◽  
Β2 Adrenergic Receptor ◽  
Sesame Lignans

Beneficial effects of sesame lignans, especially antioxidative effects, have been widely reported; however, its potential effects on autonomic nerves have not yet been investigated. Therefore, the current study aimed to investigate the effect of sesame lignans on the autonomic nervous system. The sympathetic nerve activity in rat skeletal muscle was measured using electrophysiological approaches, with blood flow determined using the laser Doppler method. Sesame lignans were administered intragastrically at 2 and 20 mg/kg, and after 60 min, the sympathetic nerve activity was observed to increase by 45.2 % and 66.1 %, respectively. A significant increase in blood flow (39.6 %) was also observed for the 20-mg/kg dose when measured at 55 min after administration. These sympathomimetic effects were completely prevented by subdiaphragmatic vagotomy, and the increase in blood flow was eliminated in the presence of the β2-adrenergic receptor inhibitor butoxamine. Thus, it is proposed that sesame lignans can increase the blood flow of skeletal muscle, possibly by exciting sympathetic nerve activity through the afferent vagal nerve.

EFFECTS OF EXERCISE ON BLOOD PRESSURE, SYMPATHETIC NERVE ACTIVITY, AND MUSCLE BLOOD FLOW RESPONSES TO HYPERINSULINEMIA IN MEN.

1998 ◽  
Vol 30 (Supplement) ◽  
pp. 213
Author(s):  
C. L.M. Forjaz ◽  
P. R. Ramires ◽  
T. Tinucci ◽  
K. C. Ortega ◽  
H. E.H. Salom??o ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Nerve Activity

Previous exercise attenuates muscle sympathetic activity and increases blood flow during acute euglycemic hyperinsulinemia

2005 ◽  
Vol 98 (3) ◽  
pp. 866-871 ◽  
Author(s):  
V. A. F. Bisquolo ◽  
C. G. Cardoso ◽  
K. C. Ortega ◽  
J. L. Gusmão ◽  
T. Tinucci ◽  
...  
Keyword(s):  
Blood Flow ◽  
Sympathetic Nerve ◽  
Sympathetic Activity ◽  
Sympathetic Nerve Activity ◽  
Insulin Infusion ◽  
Muscle Blood Flow ◽  
Dynamic Exercise ◽  
Exercise Session ◽  
Nerve Activity ◽  
Single Bout

Insulin infusion causes muscle vasodilation, despite the increase in sympathetic nerve activity. In contrast, a single bout of exercise decreases sympathetic activity and increases muscle blood flow during the postexercise period. We tested the hypothesis that muscle sympathetic activity would be lower and muscle vasodilation would be higher during hyperinsulinemia performed after a single bout of dynamic exercise. Twenty-one healthy young men randomly underwent two hyperinsulinemic euglycemic clamps performed after 45 min of seated rest (control) or bicycle exercise (50% of peak oxygen uptake). Muscle sympathetic nerve activity (MSNA, microneurography), forearm blood flow (FBF, plethysmography), blood pressure (BP, oscillometric method), and heart rate (HR, ECG) were measured at baseline (90 min after exercise or seated rest) and during hyperinsulinemic euglycemic clamps. Baseline glucose and insulin concentrations were similar in the exercise and control sessions. Insulin sensitivity was unchanged by previous exercise. During the clamp, insulin levels increased similarly in both sessions. As expected, insulin infusion increased MSNA, FBF, BP, and HR in both sessions (23 ± 1 vs. 36 ± 2 bursts/min, 1.8 ± 0.1 vs. 2.2 ± 0.2 ml·min−1·100 ml−1, 89 ± 2 vs. 92 ± 2 mmHg, and 58 ± 1 vs. 62 ± 1 beats/min, respectively, P < 0.05). BP and HR were similar between sessions. However, MSNA was significantly lower (27 ± 2 vs. 31 ± 2 bursts/min), and FBF was significantly higher (2.2 ± 0.2 vs. 1.8 ± 0.1 ml·min−1·100 ml−1, P < 0.05) in the exercise session compared with the control session. In conclusion, in healthy men, a prolonged bout of dynamic exercise decreases MSNA and increases FBF. These effects persist during acute hyperinsulinemia performed after exercise.

Blunted muscle vasodilatation during chemoreceptor stimulation in patients with heart failure

2007 ◽  
Vol 293 (1) ◽  
pp. H846-H852 ◽  
Author(s):  
Andrea Di Vanna ◽  
Ana Maria F. W. Braga ◽  
Mateus C. Laterza ◽  
Linda M. Ueno ◽  
Maria Urbana P. B. Rondon ◽  
...  
Keyword(s):  
Heart Failure ◽  
Blood Flow ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Heart Association ◽  
Functional Class ◽  
Nerve Activity ◽  
Normal Controls

Chemoreflex control of sympathetic nerve activity is exaggerated in heart failure (HF) patients. However, the vascular implications of the augmented sympathetic activity during chemoreceptor activation in patients with HF are unknown. We tested the hypothesis that the muscle blood flow responses during peripheral and central chemoreflex stimulation would be blunted in patients with HF. Sixteen patients with HF (49 ± 3 years old, Functional Class II-III, New York Heart Association) and 11 age-paired normal controls were studied. The peripheral chemoreflex control was evaluated by inhalation of 10% O2 and 90% N2 for 3 min. The central chemoreflex control was evaluated by inhalation of 7% CO2 and 93% O2 for 3 min. Muscle sympathetic nerve activity (MSNA) was directly evaluated by microneurography. Forearm blood flow was evaluated by venous occlusion plethysmography. Baseline MSNA were significantly greater in HF patients (33 ± 3 vs. 20 ± 2 bursts/min, P = 0.001). Forearm vascular conductance (FVC) was not different between the groups. During hypoxia, the increase in MSNA was significantly greater in HF patients than in normal controls (9.0 ± 1.6 vs. 0.8 ± 2.0 bursts/min, P = 0.001). The increase in FVC was significantly lower in HF patients (0.00 ± 0.10 vs. 0.76 ± 0.25 units, P = 0.001). During hypercapnia, MSNA responses were significantly greater in HF patients than in normal controls (13.9 ± 3.2 vs. 2.1 ± 1.9 bursts/min, P = 0.001). FVC responses were significantly lower in HF patients (−0.29 ± 0.10 vs. 0.37 ± 0.18 units, P = 0.001). In conclusion, muscle vasodilatation during peripheral and central chemoreceptor stimulation is blunted in HF patients. This vascular response seems to be explained, at least in part, by the exaggerated MSNA responses during hypoxia and hypercapnia.

Increased muscle perfusion reduces muscle sympathetic nerve activity during handgripping

1993 ◽  
Vol 75 (6) ◽  
pp. 2450-2455 ◽  
Author(s):  
M. J. Joyner ◽  
W. Wieling
Keyword(s):  
Blood Flow ◽  
Sympathetic Nerve ◽  
Perceived Exertion ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Maximum Voluntary Contraction ◽  
Muscle Afferents ◽  
Voluntary Contraction ◽  
Nerve Activity

This study sought to determine whether increasing blood flow to active muscles can blunt the normal rise in muscle sympathetic nerve activity (MSNA) during heavy rhythmic forearm exercise in humans. Subjects performed 5- to 6-min exercise bouts of handgripping (30/min) at 40–50% of maximum voluntary contraction (MVC). Blood flow was increased by application of suction (50 mmHg) around the forearm. Suction increased deep venous oxygen saturation in blood draining the forearm from 34 +/- 4 to 45 +/- 4%, indicating that muscle blood flow had risen by approximately 20%. Suction had no impact on the heart rate, perceived exertion, or electromyographic responses to the handgripping. During 6 min of exercise at 50% of MVC, MSNA rose from 376 +/- 67 to 970 +/- 125 units during the control trial vs. 396 +/- 69 to 729 +/- 94 units during the suction trial, and the difference was maintained during 2 min of postexercise ischemia (P < 0.05; suction < control). Mean arterial pressure (MAP) rose from 99 +/- 4 to 129 +/- 6 mmHg during control vs. 99 +/- 4 to 126 +/- 6 mmHg during the suction trial, and these responses were only different (P < 0.05; suction < control) during the final minute of the exercise bouts. During postexercise ichemia, MAP was 122 +/- 6 mmHg after the control trial but was only 112 +/- 4 mmHg after the suction trial. These results indicate that forearm suction augmented muscle blood flow, limited the activation of chemosensitive muscle afferents, and blunted the rise in MSNA during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

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