Potential Interactions Among Vascular and Muscular Functional Compartments During Active Hyperemia

2003 ◽  
Vol 28 (5) ◽  
pp. 737-753 ◽  
Author(s):  
Jack K. Barclay ◽  
Coral L. Murrant ◽  
Nancy E. Woodley ◽  
Stacey A. Reading
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Vascular System ◽  
Vascular Wall ◽  
Mammalian Skeletal Muscle ◽  
Inotropic Effects ◽  
Signal Plasticity ◽  
Bidirectional Signaling ◽  
Adventitial Layer ◽  
Upstream Direction

The increase in blood flow that accompanies the start of contractions (active hyperemia) is a complex phenomenon involving a fast phase in which blood flow increases quickly and then slows or decreases (seek phase) before stabilizing at a flow corresponding to the metabolic rate (matched phase). This pattern of blood flow change involves contributions from a flow-induced increase in flow, a response to short periods of occlusion or partial occlusion due to force generated by the muscle contraction, and metabolism. Even denervated, the vascular bed, which consists of endothelial cells, vascular smooth muscle cells, and an adventitial layer that has significant secretory potential, is able to coordinate the response pattern. Within the vascular wall, communication is possible bidirectionally across the wall and also along the wall in a retrograde or upstream direction. The signals involved, which range from endothelial cell products such as nitric oxide and endothelin to adenosine, a skeletal muscle metabolite, appear to be situation- and time-dependent. In addition to the communication potential within and along the vascular wall, signals from the vascular system are able to exert inotropic effects on mammalian skeletal muscle. Key words: bidirectional signaling, postcontraction hyperemia, flow-induced flow changes, signal plasticity

scholarly journals Peculiarities of cerebral blood flow in patients with chronic diffuse liver diseases of viral etiology

2014 ◽  
Vol 95 (6) ◽  
pp. 859-865 ◽  
Author(s):  
T S Morozova ◽  
I F Grishina ◽  
I A Gurikova
Keyword(s):  
Blood Flow ◽  
Liver Cirrhosis ◽  
Cerebral Blood Flow ◽  
Liver Diseases ◽  
Vascular System ◽  
Cerebral Arteries ◽  
Vascular Wall ◽  
Viral Etiology ◽  
The Brain ◽  
Diffuse Liver Diseases

Aim. To study the features of cerebral blood flow at different structural and functional levels of the brain vascular system in patients with chronic hepatitis and cirrhosis of viral etiology. Methods. A comprehensive ultrasound examination of the brain vascular system using an algorithm of cerebral arterial and venous blood flow examination based on the concept of the brain vascular system construction considering five structural and functional levels was performed in 65 chronic viral hepatitis patients and 61 patients with liver cirrhosis of viral etiology. The examination of the main brain arteries was performed using duplex scanning ultrasound SSD-5500 scanner («Aloka», Japan) with 5-12 MHz linear transducers. Examination of intracranial vessels was performed by transcranial color duplex scanning using ultrasonic SSD-5500 and «Sonoline G60» scanners («Siemens», Germany) with linear and phased 2.1-2.5 MHz transducers. Control group consisted of 50 healthy persons. Results. Remodeling of the cerebral arteries: the expansion of the lumen of the main cerebral vessels, reduction of blood flow in the carotid and middle cerebral arteries, decreased elasticity and increased vascular wall rigidity and, as a consequence, a change in vascular resistance and cerebral blood flow disturbance occurs in patients with chronic viral liver diseases. Identified changes of blood flow parameters at all levels of structural and functional brain perfusion indicate the presence of cerebral microangiopathy and arteriopathy based on the development of arteriosclerosis of main arteries and all penetrating arteries and arterioles in patients with chronic diffuse liver diseases. Conclusion. Adaptive remodeling of the vascular wall of the main cerebral arteries which provides an adequate regulatory response is found in patients with hepatitis B and C-associated liver cirrhosis. The reduction of blood supply to the brain, depletion of functional vascular reserve and development of intracranial venous circulatory distress are seen in patients with liver cirrhosis associated with viral hepatitis.

Effects of BAY K 8644, nifedipine, and low Ca2+ on halothane and caffeine potentiation

1991 ◽  
Vol 71 (2) ◽  
pp. 721-726 ◽  
Author(s):  
J. H. Williams ◽  
M. Holland ◽  
J. C. Lee ◽  
C. W. Ward ◽  
K. P. Davy
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Bay K 8644 ◽  
Inotropic Effect ◽  
Fiber Bundles ◽  
Mammalian Skeletal Muscle ◽  
Inotropic Effects ◽  
Twitch Potentiation

The purpose of this investigation was to examine the effects of the Ca2+ agonist BAY K 8644 and the Ca2+ antagonist nifedipine on halothane- and caffeine-induced twitch potentiation of mammalian skeletal muscle. Muscle fiber bundles were taken from normal Landrace pigs and exposed to BAY K 8644 (10 microM), nifedipine (1 microM), and low Ca2+ media administered alone and in combination with halothane (3%) or with increasing concentrations of caffeine (0.5–8.0 mM). Both BAY K 8644 and halothane potentiated twitches by approximately 80%; when they were administered in combination, twitch potentiation was nearly double that caused by either drug alone. In the presence of nifedipine, halothane increased twitches by less than 30%. Low Ca2+ significantly depressed twitches by approximately 25% but also inhibited halothane's inotropic effect. BAY K 8644 augmented caffeine potentiation but only at low caffeine concentrations (0.5–2.0 mM). Nifedipine and low Ca2+ failed to inhibit caffeine's inotropic effects. These results suggest that halothane potentiates twitches via a mechanism that involves or is influenced by extracellular Ca2+.

scholarly journals DIAGNOSTICS OF THE ELASTIC PROPERTIES OF THE VASCULAR WALL AND BLOOD FLOW VELOCITY BY ACOUSTIC METHODS

2021 ◽  
Vol 83 (4) ◽  
pp. 379-390
Author(s):  
T.S. Vikulova ◽  
I.N. Didenkulov ◽  
N.V. Pronchatov-Rubtsov ◽  
D.V. Sakharov
Keyword(s):  
Blood Flow ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Cross Section ◽  
Blood Flow Velocity ◽  
Vessel Wall ◽  
Cardiac Cycle ◽  
Vascular System ◽  
Vascular Wall ◽  
Nonlinear Acoustic

The stiffness of the vascular wall and blood flow velocity are the most important characteristics of the vascular system, which largely determine the state of health of the body. For measuring blood flow velocity, the spectral Doppler method has become widespread, which makes it possible to determine the blood velocity in a vessel, including by the shape of the Doppler spectrum – the velocity distribution in the section of large vessels. However, blood particles scattering ultrasound – erythrocytes are strongly deformed in the flow and are unevenly distributed over the cross section of the vessel. More accurate information about the velocity distribution over the cross section can be obtained by the nonlinear Doppler method, which uses microbubbles – contrast agents – as scatterers. The method is based on the generation of difference frequency waves by microbubbles when they are irradiated with two high-frequency waves having different but close frequencies.Theoretical and experimental results are presented that demonstrate the capabilities and advantages of the nonlinear acoustic difference frequency method for measuring blood flow parameters. The method makes it possible to analyze the spatio-temporal dynamics of blood flow in blood vessels during the cardiac cycle: contraction (systole) – relaxation (diastole), which makes it possible to detect violations in the bloodstream. The possibilities of determining the elasticity of the blood vessel wall have been analyzed. The method used in practice is based on measuring the speed of the pulse wave and finding the Young's modulus of the vessel wall using the Moens–Korteweg formula.To assess the stiffness of the wall of blood vessels, it is proposed to combine a nonlinear acoustic method for measuring the distribution of blood flow velocity and scanning a vessel during the cardiac cycle on the basis of a single set of ultrasound transducers. The considered methods make it possible to carry out a comprehensive diagnosis of the state of various vessels and the vascular system as a whole.

Microfluidics of blood in blood vessels stenosis

2016 ◽  
Vol 11 (2) ◽  
pp. 210-217 ◽  
Author(s):  
A.T. Akhmetov ◽  
A.A. Valiev ◽  
A.A. Rakhimov ◽  
S.P. Sametov ◽  
R.R. Habibullina
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Hydraulic Resistance ◽  
Microfluidic Device ◽  
Human Body ◽  
Vascular System ◽  
Hydrodynamic Conditions ◽  
Microstructure Change ◽  
Healthy Part

It is mentioned in the paper that hydrodynamic conditions of a flow in blood vessels with the stenosis are abnormal in relation to the total hemodynamic conditions of blood flow in a vascular system of a human body. A microfluidic device developed with a stepped narrowing for studying of the blood flow at abnormal conditions allowed to reveal blood structure in microchannels simulating the stenosis. Microstructure change is observed during the flow of both native and diluted blood through the narrowing. The study of hemorheological properties allowed us to determine an increasing contribution of the hydraulic resistance of the healthy part of the vessel during the stenosis formation.

Neural control of glucose uptake by skeletal muscle after central administration of NMDA

1995 ◽  
Vol 268 (2) ◽  
pp. R492-R497 ◽  
Author(s):  
C. H. Lang ◽  
M. Ajmal ◽  
A. G. Baillie
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Glucose Uptake ◽  
Neural Control ◽  
Plasma Insulin ◽  
Regional Blood Flow ◽  
Muscle Blood Flow ◽  
Whole Body ◽  
Glucose Disposal ◽  
Central Administration

Intracerebroventricular injection of N-methyl-D-aspartate (NMDA) produces hyperglycemia and increases whole body glucose uptake. The purpose of the present study was to determine in rats which tissues are responsible for the elevated rate of glucose disposal. NMDA was injected intracerebroventricularly, and the glucose metabolic rate (Rg) was determined for individual tissues 20-60 min later using 2-deoxy-D-[U-14C]glucose. NMDA decreased Rg in skin, ileum, lung, and liver (30-35%) compared with time-matched control animals. In contrast, Rg in skeletal muscle and heart was increased 150-160%. This increased Rg was not due to an elevation in plasma insulin concentrations. In subsequent studies, the sciatic nerve in one leg was cut 4 h before injection of NMDA. NMDA increased Rg in the gastrocnemius (149%) and soleus (220%) in the innervated leg. However, Rg was not increased after NMDA in contralateral muscles from the denervated limb. Data from a third series of experiments indicated that the NMDA-induced increase in Rg by innervated muscle and its abolition in the denervated muscle were not due to changes in muscle blood flow. The results of the present study indicate that 1) central administration of NMDA increases whole body glucose uptake by preferentially stimulating glucose uptake by skeletal muscle, and 2) the enhanced glucose uptake by muscle is neurally mediated and independent of changes in either the plasma insulin concentration or regional blood flow.

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