scholarly journals Folic acid ingestion improves skeletal muscle blood flow during graded handgrip and plantar flexion exercise in aged humans

2017 ◽  
Vol 313 (3) ◽  
pp. H658-H666 ◽  
Author(s):  
Steven A. Romero ◽  
Daniel Gagnon ◽  
Amy N. Adams ◽  
Gilbert Moralez ◽  
Ken Kouda ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Folic Acid ◽  
Muscle Blood Flow ◽  
Plantar Flexion ◽  
Serum Folate ◽  
Whole Body ◽  
Vascular Conductance ◽  
Skeletal Muscle Blood Flow ◽  
Plantar Flexion Exercise

Skeletal muscle blood flow is attenuated in aged humans performing dynamic exercise, which is due, in part, to impaired local vasodilatory mechanisms. Recent evidence suggests that folic acid improves cutaneous vasodilation during localized and whole body heating through nitric oxide-dependent mechanisms. However, it is unclear whether folic acid improves vasodilation in other vascular beds during conditions of increased metabolism (i.e., exercise). The purpose of this study was to test the hypothesis that folic acid ingestion improves skeletal muscle blood flow in aged adults performing graded handgrip and plantar flexion exercise via increased vascular conductance. Nine healthy, aged adults (two men and seven women; age: 68 ± 5 yr) performed graded handgrip and plantar flexion exercise before (control), 2 h after (acute, 5 mg), and after 6 wk (chronic, 5 mg/day) folic acid ingestion. Forearm (brachial artery) and leg (superficial femoral artery) blood velocity and diameter were measured via Duplex ultrasonography and used to calculate blood flow. Acute and chronic folic acid ingestion increased serum folate (both P < 0.05 vs. control). During handgrip exercise, acute and chronic folic acid ingestion increased forearm blood flow (both conditions P < 0.05 vs. control) and vascular conductance (both P < 0.05 vs. control). During plantar flexion exercise, acute and chronic folic acid ingestion increased leg blood flow (both P < 0.05 vs. control), but only acute folic acid ingestion increased vascular conductance ( P < 0.05 vs. control). Taken together, folic acid ingestion increases blood flow to active skeletal muscle primarily via improved local vasodilation in aged adults. NEW & NOTEWORTHY Our findings demonstrate that folic acid ingestion improves blood flow via enhanced vascular conductance in the exercising skeletal muscle of aged humans. These findings provide evidence for the therapeutic use of folic acid to improve skeletal muscle blood flow, and perhaps exercise and functional capacity, in human primary aging. Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/folic-acid-and-exercise-hyperemia-in-aging/ .

Skeletal muscle blood flow and vascular conductance are enhanced in humans with high‐affinity hemoglobin during handgrip exercise in severe hypoxia

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Chad C. Wiggins ◽  
Paolo B. Dominelli ◽  
Jonathon W. Senefeld ◽  
John R.A. Shepherd ◽  
Sarah E. Baker ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Severe Hypoxia ◽  
Handgrip Exercise ◽  
Vascular Conductance ◽  
Skeletal Muscle Blood Flow ◽  
High Affinity

scholarly journals Enhanced muscle blood flow with intermittent pneumatic compression of the lower leg during plantar flexion exercise and recovery

2018 ◽  
Vol 124 (2) ◽  
pp. 302-311 ◽  
Author(s):  
K. A. Zuj ◽  
C. N. Prince ◽  
R. L. Hughson ◽  
S. D. Peterson
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Exercise Performance ◽  
Muscle Blood Flow ◽  
Plantar Flexion ◽  
Intermittent Pneumatic Compression ◽  
Muscle Pump ◽  
Intermittent Compression ◽  
Postexercise Recovery ◽  
Plantar Flexion Exercise

This study tested the hypothesis that intermittent compression of the lower limb would increase blood flow during exercise and postexercise recovery. Data were collected from 12 healthy individuals (8 men) who performed 3 min of standing plantar flexion exercise. The following three conditions were tested: no applied compression (NoComp), compression during the exercise period only (ExComp), and compression during 2 min of standing postexercise recovery. Doppler ultrasound was used to determine superficial femoral artery (SFA) blood flow responses. Mean arterial pressure (MAP) and cardiac stroke volume (SV) were assessed using finger photoplethysmography, with vascular conductance (VC) calculated as VC = SFA flow/MAP. Compared with the NoComp condition, compression resulted in increased MAP during exercise [+3.5 ± 4.1 mmHg (mean ± SD)] but not during postexercise recovery (+1.6 ± 5.9 mmHg). SV increased with compression during both exercise (+4.8 ± 5.1 ml) and recovery (+8.0 ± 6.6 ml) compared with NoComp. There was a greater increase in SFA flow with compression during exercise (+52.1 ± 57.2 ml/min) and during recovery (+58.6 ± 56.7 ml/min). VC immediately following exercise was also significantly greater in the ExComp condition compared with the NoComp condition (+0.57 ± 0.42 ml·min−1·mmHg−1), suggesting the observed increase in blood flow during exercise was in part because of changes in VC. Results from this study support the hypothesis that intermittent compression applied during exercise and recovery from exercise results in increased limb blood flow, potentially contributing to changes in exercise performance and recovery. NEW & NOTEWORTHY Blood flow to working skeletal muscle is achieved in part through the rhythmic actions of the skeletal muscle pump. This study demonstrated that the application of intermittent pneumatic compression during the diastolic phase of the cardiac cycle, to mimic the mechanical actions of the muscle pump, accentuates muscle blood flow during exercise and elevates blood flow during the postexercise recovery period. Intermittent compression during and after exercise might have implications for exercise performance and recovery.

scholarly journals Local, but not indirect whole body heating, increases human skeletal muscle blood flow

2011 ◽  
Vol 25 (S1) ◽  
Author(s):  
Illka Heinonen ◽  
R. Matthew Brothers ◽  
Jukka Kemppainen ◽  
Juhani Knuuti ◽  
Kari K. Kalliokoski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Human Skeletal Muscle ◽  
Muscle Blood Flow ◽  
Whole Body ◽  
Skeletal Muscle Blood Flow

scholarly journals Local heating, but not indirect whole body heating, increases human skeletal muscle blood flow

2011 ◽  
Vol 111 (3) ◽  
pp. 818-824 ◽  
Author(s):  
Ilkka Heinonen ◽  
R. Matthew Brothers ◽  
Jukka Kemppainen ◽  
Juhani Knuuti ◽  
Kari K. Kalliokoski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Heat Stress ◽  
Local Heating ◽  
Muscle Blood Flow ◽  
Whole Body ◽  
Skeletal Muscle Blood Flow ◽  
Whole Body Heat Stress ◽  
Body Heat ◽  
Indirect Heating

For decades it was believed that direct and indirect heating (the latter of which elevates blood and core temperatures without directly heating the area being evaluated) increases skin but not skeletal muscle blood flow. Recent results, however, suggest that passive heating of the leg may increase muscle blood flow. Using the technique of positron-emission tomography, the present study tested the hypothesis that both direct and indirect heating increases muscle blood flow. Calf muscle and skin blood flows were evaluated from eight subjects during normothermic baseline, during local heating of the right calf [only the right calf was exposed to the heating source (water-perfused suit)], and during indirect whole body heat stress in which the left calf was not exposed to the heating source. Local heating increased intramuscular temperature of the right calf from 33.4 ± 1.0°C to 37.4 ± 0.8°C, without changing intestinal temperature. This stimulus increased muscle blood flow from 1.4 ± 0.5 to 2.3 ± 1.2 ml·100 g−1·min−1 ( P < 0.05), whereas skin blood flow under the heating source increased from 0.7 ± 0.3 to 5.5 ± 1.5 ml·100 g−1·min−1 ( P < 0.01). While whole body heat stress increased intestinal temperature by ∼1°C, muscle blood flow in the calf that was not directly exposed to the water-perfused suit (i.e., indirect heating) did not increase during the whole body heat stress (normothermia: 1.6 ± 0.5 ml·100 g−1·min−1; heat stress: 1.7 ± 0.3 ml·100 g−1·min−1; P = 0.87). Whole body heating, however, reflexively increased calf skin blood flow (to 4.0 ± 1.5 ml·100 g−1·min−1) in the area not exposed to the water-perfused suit. These data show that local, but not indirect, heating increases calf skeletal muscle blood flow in humans. These results have important implications toward the reconsideration of previously accepted blood flow distribution during whole body heat stress.

scholarly journals Is tonic sympathetic vasoconstriction increased in the skeletal muscle vasculature of aged canines?

2010 ◽  
Vol 299 (5) ◽  
pp. R1342-R1349 ◽  
Author(s):  
D. S. DeLorey ◽  
J. B. Buckwalter ◽  
S. W. Mittelstadt ◽  
M. M. Anton ◽  
H. A. Kluess ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Pyridoxal Phosphate ◽  
Muscle Blood Flow ◽  
Treadmill Running ◽  
Disulfonic Acid ◽  
Vascular Conductance ◽  
Skeletal Muscle Blood Flow ◽  
Npy Receptor ◽  
Sympathetic Vasoconstriction

We tested the hypothesis that tonic adrenergic and nonadrenergic receptor-mediated sympathetic vasoconstriction would increase at rest and during exercise with advancing age. Young ( n = 6; 22 ± 1 mo; means ± SE) and old ( n = 6; 118 ± 9 mo) beagles were studied. Selective antagonists for alpha-1, alpha-2, neuropeptide Y (NPY), and purinergic (P2x) receptors were infused at rest and during treadmill running at 2.5 mph and 4 mph with 2.5% grade. Prazosin produced similar increases in vascular conductance in young and old beagles at rest (Young: 158 ± 34%; Old: 98 ± 19%) and during exercise at 2.5 mph (Young: 80 ± 10%; Old: 58 ± 12%) and 4 mph and 2.5% grade (Young: 57 ± 5%; Old: 26 ± 4%). Rauwolscine caused similar ( P > 0.05) increases in vascular conductance in old compared with young dogs at rest (Young: 119 ± 25%; Old: 64 ± 22%) and at 2.5 mph (Young: 86 ± 13%; Old: 60 ± 7%) and 4 mph with 2.5% grade (Young: 61 ± 5%; Old: 43 ± 7%). N2-(diphenylacetyl)-N-[4-hydroxyphenyl)methyl]-d-arginine amide (BIBP) caused a smaller increase ( P < 0.05) in vascular conductance in old compared with young dogs at rest (Young: 179 ± 44%; Old: 91 ± 22%), whereas similar increases ( P > 0.05) of experimental limb vascular conductance in young and old dogs occurred following BIBP during exercise at 2.5 mph (Young: 56 ± 16%; Old: 50 ± 12%) and 4 mph and 2.5% grade (Young: 45 ± 10%; Old: 25 ± 7%). Pyridoxal-phosphate-6-azophenyl-2′-4′-disulfonic acid infusion produced a larger increase in vascular conductance in old compared with young beagles at rest (Young: 88 ± 14%; Old: 191 ± 58%), whereas similar increases were observed at 2.5 mph (Young: 47 ± 18%; Old: 31 ± 11%) and 4 mph with 2.5% grade (Young: 26 ± 13%; Old: −18 ± 8%). At rest, NPY receptor-mediated restraint of skeletal muscle blood flow was reduced with advancing age, whereas P2x receptor-mediated restraint of skeletal muscle blood flow was increased. During exercise, the magnitude of adrenergic and nonadrenergic sympathetic vasoconstriction was not different between young and old dogs. Overall, these data demonstrate that adrenergic receptor-mediated vasoconstriction was not elevated at rest, but nonadrenergic sympathetic vasoconstriction was altered under basal conditions in aged beagles.

Systemic Nitric Oxide Synthase Inhibition Increases Insulin Sensitivity in Man

1998 ◽  
Vol 94 (2) ◽  
pp. 175-180 ◽  
Author(s):  
R. Butler ◽  
A.D. Morris ◽  
A. D. Struthers
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Insulin Sensitivity ◽  
Nitric Oxide Synthase ◽  
Glucose Uptake ◽  
Muscle Blood Flow ◽  
Whole Body ◽  
Skeletal Muscle Blood Flow ◽  
Oxide Synthase

1. Recent evidence shows that skeletal muscle blood flow is an important determinant of insulin sensitivity and that insulin-mediated vasodilatation is nitric oxide dependent. These results have given rise to the hypothesis that endothelial nitric oxide inhibition may decrease insulin sensitivity in humans. 2. We examined this hypothesis directly by evaluating the effects of systemic nitric oxide synthase inhibition with NG-monomethyl l-arginine (3 mg h−1 kg−1) on whole-body glucose uptake (euglycaemic hyperinsulinaemic clamp) and calf blood flow (bilateral calf venous occlusion plethysmography) in 16 healthy male subjects in a randomized, double-blind, placebo-controlled, crossover study. 3. NG-Monomethyl l-arginine infusion was associated with a pressor effect (119/61 ± 2/2 compared with 114/58 ± 2/2 mmHg for placebo; P < 0.001), and a negative chronotropic response (57 ± 2 compared with 62 ± 2 beats/min for placebo; P < 0.001). The glucose infusion rate was significantly increased after infusion of NG-monomethyl l-arginine (8.9 ± 0.9 compared with 7.9 ± 0.8 mg min−1 kg−1 for placebo; P = 0.002). Whole-body glucose uptake increased during the clamp, with values of 9.4 ± 0.7 and 10.9 ± 0.8 mg min−1 kg−1 for placebo and NG-monomethyl l-arginine respectively (P = 0.036; 95% confidence interval 0.2,2.8). NG-Monomethyl l-arginine was associated with increased calf blood flow by comparison with placebo (P < 0.05, area under curve). 4. These data show for the first time that systemic inhibition of nitric oxide synthesis increases rather than decreases whole-body glucose uptake. We suggest that the higher skeletal muscle blood flow seen after NG-monomethyl l-arginine may explain the observed increase in whole-body glucose uptake.

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.

Biphasic effect of hydrogen peroxide on skeletal muscle arteriolar tone via activation of endothelial and smooth muscle signaling pathways

2004 ◽  
Vol 97 (3) ◽  
pp. 1130-1137 ◽  
Author(s):  
Csongor Csekő ◽  
Zsolt Bagi ◽  
Akos Koller
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Hydrogen Peroxide ◽  
Blood Flow ◽  
Smooth Muscle ◽  
Muscle Blood Flow ◽  
Skeletal Muscle Blood Flow ◽  
Local Regulation ◽  
Prostaglandin H ◽  
Arteriolar Tone

We hypothesized that hydrogen peroxide (H2O2) has a role in the local regulation of skeletal muscle blood flow, thus significantly affecting the myogenic tone of arterioles. In our study, we investigated the effects of exogenous H2O2 on the diameter of isolated, pressurized (at 80 mmHg) rat gracilis skeletal muscle arterioles (diameter of ∼150 μm). Lower concentrations of H2O2 (10−6–3 × 10−5 M) elicited constrictions, whereas higher concentrations of H2O2 (6 × 10−5–3 × 10−4 M), after initial constrictions, caused dilations of arterioles (at 10−4 M H2O2, −19 ± 1% constriction and 66 ± 4% dilation). Endothelium removal reduced both constrictions (to −10 ± 1%) and dilations (to 33 ± 3%) due to H2O2. Constrictions due to H2O2 were completely abolished by indomethacin and the prostaglandin H2/thromboxane A2 (PGH2/TxA2) receptor antagonist SQ-29548. Dilations due to H2O2 were significantly reduced by inhibition of nitric oxide synthase (to 38 ± 7%) but were unaffected by clotrimazole or sulfaphenazole (inhibitors of cytochrome P-450 enzymes), indomethacin, or SQ-29548. In endothelium-denuded arterioles, clotrimazole had no effect, whereas H2O2-induced dilations were significantly reduced by charybdotoxin plus apamin, inhibitors of Ca2+-activated K+ channels (to 24 ± 3%), the selective blocker of ATP-sensitive K+ channels glybenclamide (to 14 ± 2%), and the nonselective K+-channel inhibitor tetrabutylammonium (to −1 ± 1%). Thus exogenous administration of H2O2 elicits 1) release of PGH2/TxA2 from both endothelium and smooth muscle, 2) release of nitric oxide from the endothelium, and 3) activation of K+ channels, such as Ca2+-activated and ATP-sensitive K+ channels in the smooth muscle resulting in biphasic changes of arteriolar diameter. Because H2O2 at low micromolar concentrations activates several intrinsic mechanisms, we suggest that H2O2 contributes to the local regulation of skeletal muscle blood flow in various physiological and pathophysiological conditions.

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