Long-term electrical stimulation of rabbit skeletal muscle increases growth of paired arteries and veins

1995 ◽  
Vol 269 (2) ◽  
pp. H717-H724 ◽  
Author(s):  
T. H. Adair ◽  
J. Hang ◽  
M. L. Wells ◽  
F. D. Magee ◽  
J. P. Montani
Keyword(s):  
Skeletal Muscle ◽  
Vascular System ◽  
Common Peroneal Nerve ◽  
Numerical Density ◽  
Muscle Stimulation ◽  
Longus Muscle ◽  
The Right ◽  
Arteries And Veins ◽  
Stimulation Of

We tested whether chronic stimulation of skeletal muscle can increase the growth of paired arteries and veins in rabbit extensor digitorum longus muscle (EDL). The right EDL of female New Zealand White rabbits was stimulated via the common peroneal nerve at 10 Hz using 300 microseconds square waves at 3-4 V. Two-hour periods of stimulation was alternated with 4-h periods of rest, 7 days/wk for approximately 60 days. The left EDL served as control. The hindlimb vascular system was maximally dilated and perfuse-fixed with 3% glutaraldehyde and 2% paraformaldehyde at arterial and venous pressures of 80-100 and 15-20 mmHg, respectively. Muscles were postfixed in OsO4 and embedded in EPOX 812 resin. One millimeter-thick transverse sections were cut at uniform locations through the entire breadth of the muscle and analyzed using videomicroscopy along with computerized morphometric and stereological techniques. All paired arteries and veins on each full muscle section were analyzed. Chronic muscle stimulation caused the wall volume of paired arteries and veins to increase by an average of approximately twofold and the lumen volume to increase by an average of approximately threefold compared with the contralateral muscles. The wall-to-lumen area ratio of the arteries and veins was not affected. Muscle stimulation also caused the numerical density of arteries having a diameter > 100 microns to increase by approximately fourfold and the density of veins having a perimeter > 500 microns to increase by approximately 10-fold.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of hyperoxia and blood flow during fatigue of canine skeletal muscle in situ

1979 ◽  
Vol 47 (5) ◽  
pp. 1018-1024 ◽  
Author(s):  
J. K. Barclay ◽  
C. M. Boulianne ◽  
B. A. Wilson ◽  
S. J. Tiffin
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Experimental Period ◽  
Muscle Stimulation ◽  
Plantaris Muscle ◽  
Pentobarbital Sodium ◽  
The Right

Right and left gastrocnemius-plantaris muscle preparations in 20 dogs anesthetized with pentobarbital sodium were used to investigate the effect of hyperoxia on tension maintenance. Muscles were stimulated via the sciatic nerve for 20 min at 60 200-ms tetanic contractions/min (10 impulses/contraction). Direct muscle stimulation after the experimental period resulted in no significant change in tension. In control experiments the tension developed by the right or left muscles over the 20 min was not different. The tension developed by muscles perfused with hyperoxic blood decreased 14% after 20 min, whereas tension in the normoxic muscles decreased 35%. Blood flow in the hyperoxic muscles was significantly higher at 20 min (P less than 0.05). Pump perfusion of one of a pair of normoxic muscles resulted in a tension decrease of 13% in the pump-perfused muscles, whereas tension in the control muscles decreased 34%. Tension maintenance was flow dependent. The effect of hyperoxia could be mediated through the involvement of oxygen in the long-term control of muscle blood flow.

Effects of immobilizing the cat peroneus longus muscle on the activity of its own spindles

1993 ◽  
Vol 75 (6) ◽  
pp. 2629-2635 ◽  
Author(s):  
M. Gioux ◽  
J. Petit
Keyword(s):  
Short Length ◽  
Full Extension ◽  
Peroneus Longus ◽  
Longus Muscle ◽  
Muscle Compliance ◽  
Muscle Spindle Endings ◽  
Static Discharge ◽  
Distal Tendon ◽  
Stimulation Of

The peroneus longus muscle of 10 cats were immobilized by fixating the distal tendon on the fibula at one of two length: neutral (length for a 90 degrees flexion of the ankle joint; 5 cats) or short (length for a full extension of the joint; 5 cats). Spindle afferent discharges were studied after 2 (4 cats) or 5 wk (6 cats) of immobilization and compared with those of four control animals. In each muscle, the discharges of nearly all primary and one of secondary muscle spindle endings were recorded during 2-mm ramp-and-hold stretches applied at different initial muscle lengths. A very slight increase in both the static discharge and the dynamic index of primary endings was observed in passive spindles. The increase in connective tissue that occurs in immobilized muscle and reduces muscle compliance was likely the sole alteration responsible for this constant effect. The responses to stretches of primary endings during stimulation of static and dynamic gamma-axons were not altered. Muscle immobilization at short length, even if spindle properties are not altered, can be expected to reduce the overall amount of group Ia afferent impulses with possible long-term changes on motoneuron properties.

Characterization of the role of the AMP-activated protein kinase in the stimulation of glucose transport in skeletal muscle cells

2002 ◽  
Vol 363 (1) ◽  
pp. 167-174 ◽  
Author(s):  
Lee G.D. FRYER ◽  
Fabienne FOUFELLE ◽  
Kay BARNES ◽  
Stephen A. BALDWIN ◽  
Angela WOODS ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Phorbol Ester ◽  
Hyperosmotic Stress ◽  
Amp Activated Protein Kinase ◽  
Stimulation Of ◽  
Constitutively Active

Stimulation of AMP-activated protein kinase (AMPK) in skeletal muscle has been correlated with an increase in glucose transport. Here, we demonstrate that adenoviral-mediated expression of a constitutively active mutant of AMPKα leads to activation of glucose transport in a skeletal-muscle cell line, similar to that seen following treatment with 5-amino-imidazolecarboxamide (AICA) riboside, hyperosmotic stress or insulin. In contrast, expression of a dominant-negative form of AMPK blocked the stimulation of glucose transport by both AICA riboside and hyperosmotic stress, but was without effect on either insulin or phorbol-ester-stimulated transport. These results demonstrate that activation of AMPK is sufficient for stimulation of glucose uptake into muscle cells, and is a necessary component of the AICA riboside- and hyperosmotic-stress-induced pathway leading to increased glucose uptake. On the other hand, AMPK is not required in the insulin- or phorbol-ester-mediated pathways. Long-term (5 days) expression of the constitutively active AMPK mutant increased protein expression of GLUT1, GLUT4 and hexokinase II, consistent with previous reports on the chronic treatment of rats with AICA riboside. Expression of constitutively active AMPK had no detectable effect on p38 mitogen-activated protein kinase levels, although interestingly the level of protein kinase B was decreased. These results demonstrate that long-term activation of AMPK is sufficient to cause increased expression of specific proteins in muscle. Our results add further support to the hypothesis that long-term activation of AMPK is involved in the adaptive response of muscle to exercise training.

Renin Gene Transfer Restores Angiogenesis and VEGF Expression in Dahl S Rats

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 730-730
Author(s):  
Sandra L Amaral ◽  
Richard J Roman ◽  
Andrew S Greene
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Renin Angiotensin System ◽  
Complementation Test ◽  
Vegf Expression ◽  
Angiotensin System ◽  
Angiogenic Response ◽  
Electrical Stimulator ◽  
The Right ◽  
Stimulation Of

P204 To evaluate the importance of the renin angiotensin system (RAS) in VEGF expression and angiogenesis in skeletal muscle, we compared the angiogenic response to electrical stimulation in congenic strains of SS/Jr/Hsd rats using a complementation test design. We have previously demonstrated that both increases in VEGF expression and angiogenesis induced by electrical stimulation of skeletal muscle were absent in inbred Dahl S rats having a wildtype renin allele (S/ren ss ). In contrast, the congenic S/ren rr in which a 10 cM segment of chromosome 13 containing the normally functioning salt resistant renin allele was transferred onto the Dahl S background, exhibit the expected changes in renin. In the present study we investigate the effects of electrical stimulation on VEGF expression and angiogenesis in these rats. Congenic S/ren rr and S/ren ss rats, fed a 0.4% salt diet were surgically prepared by chronic implantation of an electrical stimulator. Another group of S/ren rr rats was treated with lisinopril, 2 days before the surgery and throughout the stimulation protocol. Rats without any drug treatment were used as control. The right tibialis anterior (TA) and extensor digitorum longus (EDL) were stimulated (10 Hz, 0.3 ms duration) for 8 hours per day for 7 days. The contralateral muscles served as controls. Western blot analysis was performed to identify VEGF protein expression in these muscles. Seven days of electrical stimulation of the skeletal muscles produced no change in vessel density of S/ren ss (Δ=5.50 ± 3.8 % and 8.14 ± 2.0 % for EDL and TA respectively). Transfer of the resistant renin allele (S/ren rr ) restored the angiogenic response (Δ=16% and 30% for EDL and TA, respectively) despite a significantly higher blood pressure (113.5 ± 2.25 mmHg and 148.67 ± 1.12 mmHg for S/ren ss and S/ren rr , respectively). Blockade of the RAS in S/ren rr restored the phenotype observed in the S/ren ss (Δ=1.46% and 1.9% to EDL and TA, respectively, p<0.05). In addition, increases in VEGF expression to electrical stimulation were observed only in S/ren rr . These results demonstrate that RAS plays an important role in the regulation of VEGF expression and angiogenesis in skeletal muscle.

Cortical Activity During Perception of Musical Pitch

2012 ◽  
Vol 30 (5) ◽  
pp. 463-479 ◽  
Author(s):  
Assal Habibi ◽  
Vinthia Wirantana ◽  
Arnold Starr
Keyword(s):  
Brain Activity ◽  
Cortical Activity ◽  
Early Age ◽  
Music Training ◽  
Functional Reorganization ◽  
The Right ◽  
P200 Amplitude ◽  
Better Than ◽  
Stimulation Of

This study investigates the effects of music training on brain activity to violations of melodic expectancies. We recorded behavioral and event-related brain potential (ERP) responses of musicians and nonmusicians to discrepancies of pitch between pairs of unfamiliar melodies based on Western classical rules. Musicians detected pitch deviations significantly better than nonmusicians. In musicians compared to nonmusicians, auditory cortical potentials to notes but not unrelated warning tones exhibited enhanced P200 amplitude generally, and in response to pitch deviations enhanced amplitude for N150 and P300 (P3a) but not N100 was observed. P3a latency was shorter in musicians compared to nonmusicians. Both the behavioral and cortical activity differences observed between musicians and nonmusicians in response to deviant notes were significant with stimulation of the right but not the left ear, suggesting that left-sided brain activity differentiated musicians from nonmusicians. The enhanced amplitude of N150 among musicians with right ear stimulation was positively correlated with earlier age onset of music training. Our data support the notion that long-term music training in musicians leads to functional reorganization of auditory brain systems, and that these effects are potentiated by early age onset of training.

scholarly journals The Location of Conduction Abnormalities in Human Entrapment Neuropathies

1976 ◽  
Vol 3 (2) ◽  
pp. 111-122 ◽  
Author(s):  
William F. Brown ◽  
Gary G. Ferguson ◽  
Michael W. Jones ◽  
Stephen K. Yates
Keyword(s):  
Peroneal Nerve ◽  
Common Peroneal Nerve ◽  
Medial Epicondyle ◽  
Direct Stimulation ◽  
Peroneus Longus ◽  
Entrapment Neuropathies ◽  
Conduction Abnormalities ◽  
Longus Muscle ◽  
The Common ◽  
Stimulation Of

SUMMARY:Direct stimulation of 23 median, 13 ulnar and 2 peroneal nerves at the time of surgical exploration has been used to locate, and characterize the conduction abnormalities in the nerves. The most frequent location of the major conduction abnormalities in the median nerve was in the first 1-2 cm distal to the origin of the carpal tunnel. In the ulnar nerve the important conduction abnormalities were located most frequently in the segments 1 cm proximal and distal to the medial epicondyle. In the peroneal nerve the major conduction abnormalities occurred proximal or distal to the entry point of the common peroneal nerve into the peroneus longus muscle.

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