Contractile properties of the myotomal muscle of sheepshead,Archosargus probatocephalus

2015 ◽  
Vol 323 (3) ◽  
pp. 169-178 ◽  
Author(s):  
David J. Coughlin ◽  
Mahfuza Akhtar
Keyword(s):  
Contractile Properties ◽  
Myotomal Muscle

scholarly journals Plasticity of muscle contractile properties following temperature acclimation in the marine fish Myoxocephalus scorpius

1995 ◽  
Vol 198 (1) ◽  
pp. 193-201 ◽  
Author(s):  
T A Beddow ◽  
I A Johnston
Keyword(s):  
High Temperatures ◽  
Power Output ◽  
Temperature Acclimation ◽  
Contractile Properties ◽  
Muscle Fibres ◽  
Contraction Speed ◽  
High K ◽  
Myoxocephalus Scorpius ◽  
Myotomal Muscle ◽  
Muscle Contractile

Live fibre bundles were isolated from the fast myotomal muscle of short-horned sculpin (Myoxocephalus scorpius L.) and isometric contractile properties and the force­velocity (P­V) relationship determined at 5, 10 and 15 °C. Experiments were carried out on winter- and summer-caught sculpins and on individuals acclimated for 6­8 weeks to either 5 or 15 °C (12 h:12 h light:dark). Maximum tetanic tension (P0) in fibres from 15 °C-acclimated fish increased from 125 kN m-2 at 5 °C to 282 kN m-2 at 15 °C (R10=2.3). For 5 °C-acclimated fish, P0 was 139 kN m-2 at 5 °C, but fell to 78 kN m-2 at 15 °C, consistent with a partial failure of excitation­contraction coupling at high temperatures. Peak force at 15 °C was increased 2.2 times following depolarisation with a high-K+ solution, but was unaffected by the addition of caffeine and/or eserine to the Ringer's solution. The results from winter- and summer-caught fish were similar to those from 5 °C- and 15 °C-acclimated sculpins respectively. In 15 °C-acclimated fish, the power output of muscle fibres calculated from the P­V relationship was 55 W kg-1 at 5 °C and 206 W kg-1 at 15 °C. The P­V relationship at 5 °C was significantly less curved in muscle fibres from 5 °C- than from 15 °C-acclimated fish. After normalizing the curves for P0 and Vmax, it was found that the change in curvature was sufficient to produce a 40 % increase in relative power output at 5 °C in cold-acclimated fish. The maximum contraction speed of muscle fibres at 15 °C was 2.4 times higher in 15 °C- than in 5 °C-acclimated fish. It was concluded that acclimation modifies the contractile properties of fast muscle fibres at both low and high temperatures.

scholarly journals Feeding muscles scale differently from swimming muscles in sunfish (Centrarchidae)

2008 ◽  
Vol 5 (2) ◽  
pp. 274-277 ◽  
Author(s):  
Andrew M Carroll ◽  
Ashley M Ambrose ◽  
Terri A Anderson ◽  
David J Coughlin
Keyword(s):  
Muscle Activation ◽  
Micropterus Salmoides ◽  
Lepomis Macrochirus ◽  
Contractile Properties ◽  
Shortening Velocity ◽  
Physiological Properties ◽  
The Family ◽  
High Power Output ◽  
Myotomal Muscle ◽  
Vertebrate Skeletal Muscle

The physiological properties of vertebrate skeletal muscle typically show a scaling pattern of slower contractile properties with size. In fishes, the myotomal or swimming muscle reportedly follows this pattern, showing slower muscle activation, relaxation and maximum shortening velocity ( V max ) with an increase in body size. We asked if the muscles involved in suction feeding by fishes would follow the same pattern. We hypothesized that feeding muscles in fishes that feed on evasive prey are under selection to maintain high power output and therefore would not show slower contractile properties with size. To test this, we compared contractile properties in feeding muscles (epaxial and sternohyoideus) and swimming muscle (myotomal) for two members of the family Centrarchidae (sunfish): the bluegill ( Lepomis macrochirus ) and the largemouth bass ( Micropterus salmoides ). Consistent with our predictions, the V max of myotomal muscle in both species slowed with size, while the epaxials showed no significant change in V max with size. In the sternohyoideus, V max slowed with size in the bluegill but increased with size in the bass. The results indicate that scaling patterns of contractile properties appear to be more closely tied to muscle function (i.e. locomotion versus feeding) than overall patterns of size.

373: The Contractile Properties of Detrusor Smooth Muscle in Cloacal Exstrophy

2007 ◽  
Vol 177 (4S) ◽  
pp. 124-124
Author(s):  
Navroop S. Johal ◽  
Peter M. Cuckow ◽  
Christopher H. Fry
Keyword(s):  
Smooth Muscle ◽  
Contractile Properties ◽  
Detrusor Smooth Muscle ◽  
Cloacal Exstrophy

scholarly journals Effects of Diacutaneous Fibrolysis on Passive Neuromuscular Response and Mechanosensitivity in Athletes with Hamstring Shortening: A Randomized Controlled Trial

2021 ◽  
Vol 18 (12) ◽  
pp. 6554
Author(s):  
Aida Cadellans-Arróniz ◽  
Carlos López-de-Celis ◽  
Albert Pérez-Bellmunt ◽  
Jacobo Rodríguez-Sanz ◽  
Luis Llurda-Almuzara ◽  
...  
Keyword(s):  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Post Treatment ◽  
Contractile Properties ◽  
Lower Limbs ◽  
Injury Incidence ◽  
Single Session ◽  
Muscle Properties ◽  
Neuromuscular Response ◽  
Control Limb

Introduction. Diacutaneous Fibrolysis is defined as specific instrumental intervention to normalize function in the musculoskeletal system. It is considered a treatment method for the mechanical alterations of the locomotor system, and it is widely used in sports for therapeutic and preventive purposes. Despite the clinical benefits observed in different musculoskeletal conditions, the action mechanism of diacutaneous fibrolysis remains uncertain. There are no studies evaluating the neuromuscular response on the posterior muscular chain of the lower extremity in athletes, where overload, stiffness, and injury incidence are high. Objective. To evaluate the immediate, and 30 min post treatment effects of a single diacutaneous fibrolysis session on passive neuromuscular response and mechanosensitibity on hamstring and gluteus in athletes with shortening. Design. A randomized within participant clinical trial. Methods. Sixty-six athletes with hamstring shortening were included (PKE < 160). The lower limbs were randomized between the experimental limb and control limb, regardless of dominance. A single session of diacutaneous fibrolysis was applied to the posterior gluteus maximus, biceps femoris, and semitendinosus of the experimental lower limb whereas the control limb was not treated. Viscoelastic muscle properties (myotonometry), contractile muscle properties (tensomiography), and mechanosensitivity (algometry) were tested before treatment (T0), after treatment (T1), and 30 min post treatment (T2). Results. Regarding viscoelastic properties, in the intra-group analysis we found statistically significant differences in the experimental limb at T1, decreasing muscle stiffness in gluteus maximus (p < 0.042), in biceps femoris (p < 0.001) and in semitendinosus (p < 0.032). We also observed statistically significant differences in Tone decrease (p < 0.011) and relaxation increase (p < 0.001) in biceps femoris. At T2, the decrease in stiffness in all tested muscles was maintained (p < 0.05). There were statistically significant inter-groups differences in stiffness on gluteus (p < 0.048) and biceps femoris (p < 0.019) and in tone on biceps femoris (p < 0.009) compared to the control limb. For contractile properties, we only found statistically significant differences on maximal radial displacement (Dm) in gluteus, both control and experimental at T2 (p < 0.05) and in biceps femoris control (p < 0.030). No changes were found in the mechanosensitivity. Conclusions. A single session of diacutaneous fibrolysis produces changes in some parameters related to viscoelasticity properties of the biceps femoris and gluteus. There were no changes on contractile properties on semitendinosus. Only small changes on the contractile properties on the gluteus maximus and biceps femoris were found. No effect was found on the mechanosensitivity of the posterior chain muscles in athletes with hamstring shortening.

Right ventricular longitudinal strain with CMR can more accurately estimate right ventricular functional reserve in rats with pulmonary arterial hypertension

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
H Sato ◽  
Y Someya ◽  
Y Takahashi ◽  
K Kumasaka ◽  
W Sato ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Right Ventricular ◽  
Longitudinal Strain ◽  
Weight Ratio ◽  
Contractile Properties ◽  
Funding Source ◽  
Functional Reserve ◽  
Pulmonary Arterial ◽  
Cmr Imaging

Abstract Background Right ventricular (RV) function is an important prognostic factor in patients with pulmonary arterial hypertension (PAH). Recently, CMR has become an attractive modality for follow up and providing prognosis in the patients, and strain has been used as a newer parameter to assess contractile properties of ventricle. It has not yet been established, however, whether RV strain with CMR can estimate RV functional reserve in the patients with PAH. Purpose We focused on CMR imaging of RV, investigating whether RV longitudinal strain can estimate RV functional reserve using a rat model with PAH. Method Rats were given a subcutaneous injection of 60 mg/kg monocrotaline (MCT-rats) or solvent (Ctr-rats). Four weeks after the injection, 25% of MCT-rats died due to RV failure. In the survivors of MCT- (n=19) and Ctr-rats (n=5), retrospective ECG-gated cine MR (16 phases/beat) was imaged with a 7T scanner. Subsequently, we measured RV pressure (RVP) via right internal jugular vein and dissected trabeculae (length = 1.45±0.07 mm, width = 334±27 μm, thickness = 114±6 μm) from RVs. We calculated weight ratio of RV free wall to left ventricle (LV) by RV/(LV+septum). Trabeculae were electrically stimulated with 2-s stimulus intervals, and force was measured using a silicon strain gauge (0.7 mM extracellular Ca2+, 24°C). To determine contractile properties of RV muscle, dF/dt was calculated. Using CMR imaging, we measured RV ejection fraction (RVEF) and RV longitudinal strain (RVLS). To modulate RVP, we intravenously injected 5 nmol endothelin-1 (ET-1) and again measured RVEF and RVLS. Results MCT-rats showed higher systolic RVP (62.5±16.6 vs. 25.9±1.86 mmHg, p&lt;0.01) and higher weight ratio of RV (0.60±0.03 vs. 0.28±0.02, p&lt;0.05). In CMR imaging, MCT-rats showed lower RVEF (36.1±11.2 vs. 64.8±8.4%, p&lt;0.001) and lower RVLS (−18±9 vs. −30±1%, p&lt;0.05). In trabeculae from RVs, MCT-rats showed lower developed force and lower dF/dt (p&lt;0.01). Correlation between RVLS and dF/dt was higher (n=20, r=0.53, p&lt;0.05) than that between RVEF and dF/dt (r=0.24). In addition, RVLS and dF/dt had already been decreased in 5 MCT-rats with relatively preserved RVEF (&gt;50%), suggesting that RVLS decreases earlier than RVEF in MCT-rats. Ten minutes after the injection of ET-1, RVP was increased from 49.4±7.9 to 57.9±6.4 mmHg in MCT-rats (n=6). In MCT-rats with preserved RVEF and decreased RVLS, the increase in RVP chiefly decreased RVEF while it did not change RVLS and RVEF in Ctr-rats, meaning that RV functional reserve had been decreased in MCT-rats. In trabeculae, developed force and dF/dt were increased after the addition of 0.1 μM ET-1 in MCT- (n=11, p&lt;0.01) and Ctr-rats (n=4, p&lt;0.01). Conclusion These results suggest that in rats with PAH, RVLS obtained from CMR can estimate RV functional reserve earlier and more accurately than RVEF. Therefore, RV strain with CMR may become an important parameter to assess RV functional reserve in patients with PAH. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Young Scientists

Sign in / Sign up

Export Citation Format

Share Document