scholarly journals Limb movement-induced hyperemia has a central hemodynamic component: evidence from a neural blockade study

2010 ◽  
Vol 299 (5) ◽  
pp. H1693-H1700 ◽  
Author(s):  
Joel D. Trinity ◽  
Markus Amann ◽  
John McDaniel ◽  
Anette S. Fjeldstad ◽  
Zachary Barrett-O'Keefe ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Knee Extension ◽  
Muscle Afferents ◽  
Limb Movement ◽  
Passive Movement ◽  
Afferent Feedback ◽  
Maximal Response ◽  
Before And After ◽  
Central Hemodynamic ◽  
Hyperemic Response

The purpose of this investigation was to partially remove feedback from type III/IV skeletal muscle afferents and determine how this feedback influences the central and peripheral hemodynamic responses to passive leg movement. Heart rate (HR), stroke volume (SV), cardiac output (CO), mean arterial pressure, leg vascular conductance (LVC), and leg blood flow (LBF) were measured during 2 min of passive knee extension in eight young men before and after intrathecal fentanyl injection. Passive movement increased HR by 14 beats/min from baseline to maximal response during control (CON) (65 ± 4 to 79 ± 5 beats/min, P < 0.05), whereas HR did not significantly increase with the fentanyl block (BLK). LBF and LVC increased in both conditions; however, these increases were attenuated and delayed during BLK [%change from baseline to maximum, LBF: CON 295 ± 109 vs. BLK 210 ± 86%, ( P < 0.05); LVC: CON 322 ± 40% vs. BLK 231 ± 32%, ( P < 0.04)]. In CON, HR, SV, CO, and LVC increased contributing to the hyperemic response. However, under BLK conditions, statistically insignificant increases in HR and SV combined to yield a small, but significant, increase in CO and an attenuated hyperemic response. Therefore, partially blocking skeletal muscle afferent feedback blunts the central hemodynamic response due to passive limb movement, which then results in an attenuated and delayed movement-induced hyperemia. In combination, these findings provide evidence that limb movement-induced hyperemia has a significant central hemodynamic component induced by peripheral nerve activation.

scholarly journals Passive limb movement: evidence of mechanoreflex sex specificity

2013 ◽  
Vol 304 (1) ◽  
pp. H154-H161 ◽  
Author(s):  
Stephen J. Ives ◽  
John McDaniel ◽  
Melissa A. H. Witman ◽  
Russell S. Richardson
Keyword(s):  
Heart Rate ◽  
Cardiac Index ◽  
Stroke Volume ◽  
Limb Movement ◽  
Passive Movement ◽  
Stroke Index ◽  
Vascular Conductance ◽  
Hemodynamic Responses ◽  
Central Hemodynamic ◽  
Sex Specificity

Previous studies have determined that premenopausal women exhibit an attenuated metaboreflex; however, little is known about sex specificity of the mechanoreflex. Thus, we sought to determine if sex differences exist in the central and peripheral hemodynamic responses to passive limb movement. Second-by-second measurements of heart rate, stroke volume, cardiac output (CO), mean arterial pressure, and femoral artery blood flow (FBF) were recorded during 3 min of supine passive knee extension in 24 young healthy subjects (12 women and 12 men). Normalization of CO and stroke volume to body surface area, expressed as cardiac index and stroke index, eliminated differences in baseline central hemodynamics, whereas, peripherally, basal FBF and femoral vascular conductance were similar between the sexes. In response to passive limb movement, women displayed significantly attenuated peak central hemodynamic responses compared with men (heart rate: 9.0 ± 1 vs. 14.8 ± 2% change, stroke index: 4.5 ± 0.6 vs. 7.8 ± 1.2% change, cardiac index: 9.6 ± 1 vs. 17.2 ± 2% change, all P < 0.05), whereas movement induced similar increases in peak FBF (167 ± 32 vs. 193 ± 17% change) and femoral vascular conductance (172 ± 31 vs. 203 ± 16% change) in both sexes (women vs. men, respectively). Additionally, there was a significant positive relationship between individual peak FBF and peak CO response to passive movement in men but not in women. Thus, although both sexes exhibited similar movement-induced hyperemia and peripheral vasodilatory function, the central hemodynamic response was blunted in women, implying an attenuated mechanoreflex. Therefore, this study reveals that, as already recognized with the metaboreflex, there is likely a sex-specific attenuation of the mechanoreflex in women.

scholarly journals Impact of body position on central and peripheral hemodynamic contributions to movement-induced hyperemia: implications for rehabilitative medicine

2011 ◽  
Vol 300 (5) ◽  
pp. H1885-H1891 ◽  
Author(s):  
Joel D. Trinity ◽  
John McDaniel ◽  
Massimo Venturelli ◽  
Anette S. Fjeldstad ◽  
Stephen J. Ives ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Perfusion Pressure ◽  
Body Position ◽  
Knee Extension ◽  
Passive Movement ◽  
Hemodynamic Responses ◽  
Peripheral Hemodynamics ◽  
Central Response ◽  
Central Hemodynamic ◽  
Sustained Increase

This study used alterations in body position to identify differences in hemodynamic responses to passive exercise. Central and peripheral hemodynamics were noninvasively measured during 2 min of passive knee extension in 14 subjects, whereas perfusion pressure (PP) was directly measured in a subset of 6 subjects. Movement-induced increases in leg blood flow (LBF) and leg vascular conductance (LVC) were more than twofold greater in the upright compared with supine positions (LBF, supine: 462 ± 6, and upright: 1,084 ± 159 ml/min, P < 0.001; and LVC, supine: 5.3 ± 1.2, and upright: 11.8 ± 2.8 ml·min−1·mmHg−1, P < 0.002). The change in heart rate (HR) from baseline to peak was not different between positions (supine: 8 ± 1, and upright: 10 ± 1 beats/min, P = 0.22); however, the elevated HR was maintained for a longer duration when upright. Stroke volume contributed to the increase in cardiac output (CO) during the upright movement only. CO increased in both positions; however, the magnitude and duration of the CO response were greater in the upright position. Mean arterial pressure and PP were higher at baseline and throughout passive movement when upright. Thus exaggerated central hemodynamic responses characterized by an increase in stroke volume and a sustained HR response combined to yield a greater increase in CO during upright movement. This greater central response coupled with the increased PP and LVC explains the twofold greater and more sustained increase in movement-induced hyperemia in the upright compared with supine position and has clinical implications for rehabilitative medicine.

scholarly journals Understanding exercise-induced hyperemia: central and peripheral hemodynamic responses to passive limb movement in heart transplant recipients

2010 ◽  
Vol 299 (5) ◽  
pp. H1653-H1659 ◽  
Author(s):  
Melissa A. Hayman ◽  
Jose N. Nativi ◽  
Josef Stehlik ◽  
John McDaniel ◽  
Anette S. Fjeldstad ◽  
...  
Keyword(s):  
Heart Transplant ◽  
Vascular Function ◽  
Knee Extension ◽  
Limb Movement ◽  
Passive Movement ◽  
Peripheral Vascular ◽  
Femoral Artery Blood Flow ◽  
Femoral Blood ◽  
Exercise Induced ◽  
Artery Flow

To better characterize the contribution of both central and peripheral mechanisms to passive limb movement-induced hyperemia, we studied nine recent (<2 yr) heart transplant (HTx) recipients (56 ± 4 yr) and nine healthy controls (58 ± 5 yr). Measurements of heart rate (HR), stroke volume (SV), cardiac output (CO), and femoral artery blood flow were recorded during passive knee extension. Peripheral vascular function was assessed using brachial artery flow-mediated dilation (FMD). During passive limb movement, the HTx recipients lacked an HR response (0 ± 0 beats/min, Δ0%) but displayed a significant increase in CO (0.4 ± 0.1 l/min, Δ5%) although attenuated compared with controls (1.0 ± 0.2 l/min, Δ18%). Therefore, the rise in CO in the HTx recipients was solely dependent on increased SV (5 ± 1 ml, Δ5%) in contrast with the controls who displayed significant increases in both HR (6 ± 2 beats/min, Δ11%) and SV (5 ± 2 ml, Δ7%). The transient increase in femoral blood volume entering the leg during the first 40 s of passive movement was attenuated in the HTx recipients (24 ± 8 ml) compared with controls (93 ± 7 ml), whereas peripheral vascular function (FMD) appeared similar between HTx recipients (8 ± 2%) and controls (6 ± 1%). These data reveal that the absence of an HR increase in HTx recipients significantly impacts the peripheral vascular response to passive movement in this population and supports the concept that an increase in CO is a major contributor to exercise-induced hyperemia.

Vitamin B6 Deficiency can Reduce Fuel Storage and Utilization in Physically Trained Rats

2008 ◽  
Vol 78 (2) ◽  
pp. 64-69 ◽  
Author(s):  
Choi ◽  
Cho
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Muscle Protein ◽  
Plasma Free Fatty Acid ◽  
Vitamin B ◽  
Liver Protein ◽  
Protein Levels ◽  
Before And After ◽  
Fuel Storage ◽  
Exercise Muscle

This study investigated the effect of vitamin B6 deficiency on the utilization and recuperation of stored fuel in physically trained rats. 48 rats were given either vitamin B6-deficient (B6–) diet or control (B6+) diet for 4 weeks and were trained on treadmill for 30 minutes daily. All animals were then subdivided into 3 groups: before-exercise (BE); during-exercise (DE); after-exercise (AE). The DE group was exercised on treadmill for 1 hour just before being sacrificed. Animals in the AE group were allowed to take a rest for 2 hours after being exercised like the DE group. Glucose and free fatty acids were compared in plasma. Glycogen and triglyceride were compared in liver and skeletal muscle. Protein levels were compared in plasma, liver, and skeletal muscle. Compared with the B6+ group, plasma glucose levels of the B6– group were significantly lower before and after exercise. Muscle glycogen levels of the B6– group were significantly lower than those of the B6+ group regardless of exercise. The liver glycogen level of the B6– group was also significantly lower than that of B6+ group during and after exercise. Before exercise, plasma free fatty acid levels were not significantly different between the B6+ and B6– groups, and plasma free fatty acid levels of the B6– group were significantly lower during and after exercise. The muscle triglyceride level of the B6– group was significantly lower than that of the B6+ group before exercise, and there were no differences between B6+ and B6– groups during and after exercise. Liver triglyceride levels were not significantly different between B6+ and B6– groups. Plasma protein levels of the B6– group were lower than those of B6+ before and after exercise. Muscle protein levels of the B6– group were not significantly different from those of the B6+ group. Liver protein levels of the B6– group were significantly lower than that of the B6+ group after exercise. Liver protein levels of both B6+ and B6– groups were not significantly changed, regardless of exercise. Thus, it is suggested that vitamin B6 deficiency may reduce fuel storage and utilization with exercise in physically trained rats.

Methacholine-induced bronchoconstriction in dogs: effects of lung volume and O3 exposure

1988 ◽  
Vol 65 (6) ◽  
pp. 2679-2686 ◽  
Author(s):  
S. T. Kariya ◽  
S. A. Shore ◽  
W. A. Skornik ◽  
K. Anderson ◽  
R. H. Ingram ◽  
...  
Keyword(s):  
Lung Volume ◽  
Maximal Response ◽  
Maximal Effect ◽  
Response Curves ◽  
Lung Volumes ◽  
Before And After ◽  
Residual Capacity ◽  
Induced Changes ◽  
Conducting Airways ◽  
Concentration Response Curve

The maximal effect induced by methacholine (MCh) aerosols on pulmonary resistance (RL), and the effects of altering lung volume and O3 exposure on these induced changes in RL, was studied in five anesthetized and paralyzed dogs. RL was measured at functional residual capacity (FRC), and lung volumes above and below FRC, after exposure to MCh aerosols generated from solutions of 0.1-300 mg MCh/ml. The relative site of response was examined by magnifying parenchymal [RL with large tidal volume (VT) at fast frequency (RLLS)] or airway effects [RL with small VT at fast frequency (RLSF)]. Measurements were performed on dogs before and after 2 h of exposure to 3 ppm O3. MCh concentration-response curves for both RLLS and RLSF were sigmoid shaped. Alterations in mean lung volume did not alter RLLS; however, RLSF was larger below FRC than at higher lung volumes. Although O3 exposure resulted in small leftward shifts of the concentration-response curve for RLLS, the airway dominated index of RL (RLSF) was not altered by O3 exposure, nor was the maximal response using either index of RL. These data suggest O3 exposure does not affect MCh responses in conducting airways; rather, it affects responses of peripheral contractile elements to MCh, without changing their maximal response.

scholarly journals CORP: Ultrasound assessment of vascular function with the passive leg movement technique

2017 ◽  
Vol 123 (6) ◽  
pp. 1708-1720 ◽  
Author(s):  
Jayson R. Gifford ◽  
Russell S. Richardson
Keyword(s):  
Vascular Function ◽  
Cardiovascular Health ◽  
Vascular System ◽  
The Elderly ◽  
Passive Movement ◽  
Flow Mediated Dilation ◽  
Peripheral Vascular ◽  
Ultrasound Assessment ◽  
Leg Movement ◽  
Hyperemic Response

As dysfunction of the vascular system is an early, modifiable step in the progression of many cardiovascular diseases, there is demand for methods to monitor the health of the vascular system noninvasively in clinical and research settings. Validated by very good agreement with more technical assessments of vascular function, like intra-arterial drug infusions and flow-mediated dilation, the passive leg movement (PLM) technique has emerged as a powerful, yet relatively simple, test of peripheral vascular function. In the PLM technique, the change in leg blood flow elicited by the passive movement of the leg through a 90° range of motion is quantified with Doppler ultrasound. This relatively easy-to-learn test has proven to be ≤80% dependent on nitric oxide bioavailability and is especially adept at determining peripheral vascular function across the spectrum of cardiovascular health. Indeed, multiple reports have documented that individuals with decreased cardiovascular health such as the elderly and those with heart failure tend to exhibit a substantially blunted PLM-induced hyperemic response (~50 and ~85% reduction, respectively) compared with populations with good cardiovascular health such as young individuals. As specific guidelines have not yet been put forth, the purpose of this Cores of Reproducibility in Physiology (CORP) article is to provide a comprehensive reference for the assessment and interpretation of vascular function with PLM with the aim to increase reproducibility and consistency among studies and facilitate the use of PLM as a research tool with clinical relevance.

Muscle glycogen availability and temperature regulation in humans

1989 ◽  
Vol 66 (1) ◽  
pp. 72-78 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Temperature Regulation ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Before And After ◽  
Muscle Groups

The effects of intramuscular glycogen availability on human temperature regulation were studied in eight seminude subjects immersed in 18 degrees C water for 90 min or until rectal temperature (Tre) decreased to 35.5 degrees C. Each subject was immersed three times over a 3-wk period. Each immersion followed 2.5 days of a specific dietary and/or exercise regimen designed to elicit low (L), normal (N), or high (H) glycogen levels in large skeletal muscle groups. Muscle glycogen concentration was determined in biopsies taken from the vastus lateralis muscle before and after each immersion. Intramuscular glycogen concentration before the immersion was significantly different among the L, N, and H trials (P less than 0.01), averaging 247 +/- 15, 406 +/- 23, and 548 +/- 42 (SE) mmol glucose units.kg dry muscle-1, respectively. The calculated metabolic heat production during the first 30 min of immersion was significantly lower during L compared with N or H (P less than 0.05). The rate at which Tre decreased was more rapid during the L immersion than either N or H (P less than 0.05), and the time during the immersion at which Tre first began to decrease also appeared sooner during L than N or H. The results suggest that low skeletal muscle glycogen levels are associated with more rapid body cooling during water immersion in humans. Higher than normal muscle glycogen levels, however, do not increase cold tolerance.

scholarly journals Regulation of angiopoietin-like protein 4/fasting-induced adipose factor (Angptl4/FIAF) expression in mouse white adipose tissue and 3T3-L1 adipocytes

2008 ◽  
Vol 100 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Sarah Dutton ◽  
Paul Trayhurn
Keyword(s):  
Skeletal Muscle ◽  
Cell Culture ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Culture Medium ◽  
Mrna Level ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Before And After ◽  
Stimulation Of

Angiopoietin-like protein 4 (Angptl4)/FIAF (fasting-induced adipose factor) was first identified as a target for PPAR and to be strongly induced in white adipose tissue (WAT) by fasting. Here we have examined the regulation of the expression and release of this adipokine in mouse WAT and in 3T3-L1 adipocytes. Angptl4/FIAF expression was measured by RT-PCR and real-time PCR; plasma Angptl4/FIAF and release of the protein in cell culture was determined by western blotting. The Angptl4/FIAF gene was expressed in each of the major WAT depots of mice, the mRNA level in WAT being similar to the liver and much higher (>50-fold) than skeletal muscle. Fasting mice (18 h) resulted in a substantial increase in Angptl4/FIAF mRNA in liver and muscle (9·5- and 21-fold, respectively); however, there was no effect of fasting on Angptl4/FIAF mRNA in WAT and the plasma level of Angptl4/FIAF was unchanged. The Angptl4/FIAF gene was expressed in 3T3-L1 adipocytes before and after differentiation, the level increasing post-differentiation; Angptl4/FIAF was released into the culture medium. Insulin, leptin, dexamethasone, noradrenaline, TNFα and several IL (IL-1β, IL-6, IL-10, IL-18) had little effect on Angptl4/FIAF mRNA levels in 3T3-L1 adipocytes. However, a major stimulation of Angptl4/FIAF expression was observed with rosiglitazone and the inflammatory prostaglandins PGD2 and PGJ2. Angptl4/FIAF does not act as an adipose tissue signal of nutritional status, but is markedly induced by fasting in liver and skeletal muscle.

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