scholarly journals Effects of Cilnidipine on Muscle Fiber Composition, Capillary Density and Muscle Blood Flow in Fructose-Fed Rats.

2001 ◽  
Vol 24 (5) ◽  
pp. 565-572 ◽  
Author(s):  
Mikio TAKADA ◽  
Nobuyuki URA ◽  
Katsuhiro HIGASHIURA ◽  
Hideyuki MURAKAMI ◽  
Nobuhiko TOGASHI ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Fiber ◽  
Muscle Blood Flow ◽  
Capillary Density ◽  
Fiber Composition

Muscle blood flow patterns during exercise in partially curarized rats

1985 ◽  
Vol 58 (3) ◽  
pp. 698-701 ◽  
Author(s):  
R. B. Armstrong ◽  
C. B. Vandenakker ◽  
M. H. Laughlin
Keyword(s):  
Blood Flow ◽  
Muscle Fiber ◽  
Treadmill Exercise ◽  
Muscle Blood Flow ◽  
Flow Patterns ◽  
Physical Factors ◽  
Low Speed ◽  
Factors Associated ◽  
Red Muscle ◽  
Blood Flow Patterns

We studied the distribution of blood flow within and among muscles of partially curarized (40–100 micrograms/kg body wt) rats during preexercise and at 1 min of low-speed treadmill exercise (15 m/min). Glycogen loss in the deep red muscles and parts of muscles was significantly reduced in the curarized animals during exercise, indicating the fibers in these muscles were recruited to a lesser extent and/or had lower metabolisms than fibers in the same muscles of control rats. However, elevations in blood flow in the red muscles of the curarized rats were as great or greater than those in the control rats. Thus reduced recruitment and/or metabolism of the deep red muscle fibers of the curarized animals was not accompanied by reduced blood flow. These findings suggest a dissociation between red fiber metabolism and blood flow in the curarized rats during the 1st min of slow treadmill exercise and indicate that release of vasodilator substances or local physical factors associated with muscle fiber activity are not solely responsible for the initial hyperemia during exercise.

Physical fitness, muscle morphology, and insulin-stimulated limb blood flow in normal subjects

1996 ◽  
Vol 270 (5) ◽  
pp. E905-E911 ◽  
Author(s):  
T. Utriainen ◽  
A. Holmang ◽  
P. Bjorntorp ◽  
S. Makimattila ◽  
A. Sovijarvi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Physical Fitness ◽  
Muscle Fiber ◽  
Aerobic Power ◽  
Normal Subjects ◽  
Maximal Aerobic Power ◽  
Whole Body ◽  
Limb Blood Flow ◽  
Muscle Morphology ◽  
Fiber Composition

The response of limb blood flow to insulin is highly variable even in normal subjects. We examined whether physical fitness or differences in muscle morphology contribute to this variation. Maximal aerobic power, muscle fiber composition and capillarization, and the response of forearm glucose extraction and blood flow to a sequential hyperinsulinemic euglycemic clamp (serum insulin 374 +/- 10, 816 +/- 23, and 2,768 +/- 78 pmol/l) were determined in 16 normal males (age 25 +/- 1 yr, body mass index 24 +/- 1 kg/m2). Maximal aerobic power correlated positively with the proportion of type I fibers (r = 0.67, P < 0.01) and negatively with the proportion of type IIb fibers (r = -0.73, P < 0.01). Fiber composition but not blood flow correlated significantly with forearm and whole body glucose uptake. All doses of insulin significantly increased forearm blood flow, maximally by 123 +/- 21%. The ratio of capillaries per fiber was significantly correlated with basal and insulin-stimulated blood flow (0.58∑ 0.76, P < 0.05∑0.01). Mean arterial blood pressure and the insulin∑induced increase in blood flow were inversely correlated (r = ∑0.59, P < 0.05). We conclude that variation in glucose extraction is significantly determined by muscle fiber composition, whereas variation in insulin-stimulated blood flow is closely associated with muscle capillarization.

Muscle Fiber Composition and Capillary Density in Women and Men With NIDDM

Diabetes Care ◽  
1994 ◽  
Vol 17 (5) ◽  
pp. 382-386 ◽  
Author(s):  
P. MArin ◽  
B. Andersson ◽  
M. Krotkiewski ◽  
P. Bjorntorp
Keyword(s):  
Muscle Fiber ◽  
Capillary Density ◽  
Fiber Composition

Oxidative capacity, blood flow, and capillarity of skeletal muscles

1980 ◽  
Vol 49 (4) ◽  
pp. 627-633 ◽  
Author(s):  
L. C. Maxwell ◽  
T. P. White ◽  
J. A. Faulkner
Keyword(s):  
Blood Flow ◽  
Skeletal Muscles ◽  
Muscle Blood Flow ◽  
Muscle Fibers ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Histochemical Demonstration ◽  
Capillary Endothelium ◽  
Fiber Types ◽  
Fiber Area

Our purpose was to test the hypothesis that the capillarity of mammalian skeletal muscles is correlated with the oxidate capacity of muscle fibers, or with the capacity for maximum blood flow. Capillarity of skeletal muscles from several species was determined using histochemical demonstration of phosphatase activity of capillary endothelium. Serial sections were incubated for succinate dehydrogenase activity as an indicator of muscle fiber oxidative capacity, and for myofibrillar ATPase activity. three types of muscle fibers were identified. Fiber area was determined by planimetry of projected cross sections. Succinate oxidase activity of whole homogenates was determined by differential respirometry. Muscle blood flow was determined experimentally or data were obtained from the literature. No consistent relation was observed for the different fiber types in the number of adjacent capillaries. Capillary density was negatively correlated with mean fiber area. Among adult animals of several species, skeletal muscles representing a 17-fold range of oxidative capacity demonstrated no relation between capillarity and oxidative capacity or muscle blood flow at maximum oxygen uptake. We find no support for relations between oxidative capacity of muscle blood flow and the capillarity of whole muscle or individual fibers and reject the hypothesis.

scholarly journals Muscle Fiber Composition and Capillary Density in Turner Syndrome: Evidence of increased muscle fiber size related to insulin resistance

Diabetes Care ◽  
2001 ◽  
Vol 24 (9) ◽  
pp. 1668-1673 ◽  
Author(s):  
C. H. Gravholt ◽  
B. Nyholm ◽  
B. Saltin ◽  
O. Schmitz ◽  
J. S. Christiansen
Keyword(s):  
Insulin Resistance ◽  
Turner Syndrome ◽  
Muscle Fiber ◽  
Capillary Density ◽  
Fiber Composition ◽  
Fiber Size

scholarly journals Influence of contractile work and muscle fiber recruitment on skeletal muscle blood flow in humans

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Jennifer Clarke Richards ◽  
Anne R. Crecelius ◽  
Brett S Kirby ◽  
Frank A. Dinenno
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Fiber ◽  
Muscle Blood Flow ◽  
Skeletal Muscle Blood Flow

Hemodynamics and O2 uptake during maximal knee extensor exercise in untrained and trained human quadriceps muscle: effects of hyperoxia

2004 ◽  
Vol 97 (5) ◽  
pp. 1796-1802 ◽  
Author(s):  
M. Mourtzakis ◽  
J. González-Alonso ◽  
T. E. Graham ◽  
B. Saltin
Keyword(s):  
Blood Flow ◽  
Peak Power ◽  
Fiber Type ◽  
Muscle Blood Flow ◽  
Knee Extensor ◽  
Capillary Density ◽  
Quadriceps Muscle ◽  
Peak Power Output ◽  
Vascular Conductance ◽  
Type Composition

To elucidate the potential limitations on maximal human quadriceps O2 capacity, six subjects trained (T) one quadriceps on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). Following 5 wk of training, subjects underwent incremental knee extensor tests under normoxic (inspired O2 fraction = 21%) and hyperoxic (inspired O2 fraction = 60%) conditions with the T and UT quadriceps. Training increased quadriceps muscle mass (2.9 ± 0.2 to 3.1 ± 0.2 kg), but did not change fiber-type composition or capillary density. The T quadriceps performed at a greater peak power output than UT, under both normoxia (101 ± 10 vs. 80 ± 7 W; P < 0.05) and hyperoxia (97 ± 11 vs. 81 ± 7 W; P < 0.05) without further increases with hyperoxia. Similarly, thigh peak O2 consumption, blood flow, vascular conductance, and O2 delivery were greater in the T vs. the UT thigh (1.4 ± 0.2 vs. 1.1 ± 0.1 l/min, 8.4 ± 0.8 vs. 7.2 ± 0.8 l/min, 42 ± 6 vs. 35 ± 4 ml·min−1·mmHg−1, 1.71 ± 0.18 vs. 1.51 ± 0.15 l/min, respectively) but were not enhanced with hyperoxia. Oxygen extraction was elevated in the T vs. the UT thigh, whereas arteriovenous O2 difference tended to be higher (78 ± 2 vs. 72 ± 4%, P < 0.05; 160 ± 8 vs. 154 ± 11 ml/l, respectively; P = 0.098) but again were unaltered with hyperoxia. In conclusion, the present results demonstrate that the increase in quadriceps muscle O2 uptake with training is largely associated with increases in blood flow and O2 delivery, with smaller contribution from increases in O2 extraction. Furthermore, the elevation in peak muscle blood flow and vascular conductance with endurance training seems to be related to an enhanced vasodilatory capacity of the vasculature perfusing the quadriceps muscle that is unaltered by moderate hyperoxia.

Adrenoreceptor effects on rat muscle blood flow during treadmill exercise

1987 ◽  
Vol 62 (4) ◽  
pp. 1465-1472 ◽  
Author(s):  
M. H. Laughlin ◽  
R. B. Armstrong
Keyword(s):  
Blood Flow ◽  
Muscle Fiber ◽  
Treadmill Exercise ◽  
Fiber Type ◽  
Muscle Blood Flow ◽  
Beta Blockade ◽  
Beta Receptor ◽  
Extensor Muscles ◽  
Alpha Blockade ◽  
Total Muscle

The purpose of this study was to examine the effects of the adrenergic receptors on the distribution of blood flow within and among skeletal muscles in rats. Blood flow was measured with the radiolabeled microsphere technique before exercise and during treadmill exercise at 15 or 60 m/min. Alpha- (phentolamine) or beta- (propranolol) adrenergic blocking drugs were administered, and then blood flow was measured and results compared with those from saline-treated rats. Before exercise, alpha-blockade caused increases in total muscle blood flow and in all fast-twitch muscles, whereas muscles composed of greater than 20% slow-twitch fibers showed no effect. During exercise at 15 m/min, the normal increase in total muscle blood flow was attenuated by alpha-blockade. Compared with controls, blood flow was less in the high-oxidative (fast and slow) muscle fiber areas of extensor muscles, whereas blood flow to white areas of extensor muscles was increased. beta-Blockade tended to decrease muscle blood flow before exercise and during exercise at 15 m/min with no apparent relationship between the effects of blockade on blood flow and muscle fiber type. These effects of beta-blockade were not apparent during exercise at 60 m/min. We conclude that before exercise alpha-receptor effects are limited to fast muscle, whereas beta-receptor influences are independent of fiber type, beta-receptors contribute to the initial hyperemia of exercise at 15 m/min, and beta-receptor influence is inversely related to metabolic rate.

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