Influence of myosin isoforms on contractile properties of intact muscle fibers from Rana pipiens

2002 ◽  
Vol 282 (4) ◽  
pp. C835-C844 ◽  
Author(s):  
Gordon J. Lutz ◽  
Shashank R. Sirsi ◽  
Sarah A. Shapard-Palmer ◽  
Shannon N. Bremner ◽  
Richard L. Lieber
Keyword(s):  
Myosin Light Chain ◽  
Rana Pipiens ◽  
Isometric Tension ◽  
Myosin Isoforms ◽  
Shortening Velocity ◽  
Cross Sectional ◽  
Sds Page ◽  
Intact Muscle ◽  
Force Velocity ◽  
Fast Twitch

The myosin heavy chain (MHC) and myosin light chain (MLC) isoforms in skeletal muscle of Rana pipiens have been well characterized. We measured the force-velocity (F- V) properties of single intact fast-twitch fibers from R. pipiens that contained MHC types 1 or 2 (MHC1 or MHC2) or coexpressed MHC1 and MHC2 isoforms. Velocities were measured between two surface markers that spanned most of the fiber length. MHC and MLC isoform content was quantified after mechanics analysis by SDS-PAGE. Maximal shortening velocity ( V max) and velocity at half-maximal tension ( V P 50) increased with percentage of MHC1 (%MHC1). Maximal specific tension (Po/CSA, where Po is isometric tension and CSA is fiber cross-sectional area) and maximal mechanical power ( W max) also increased with %MHC1. MHC concentration was not significantly correlated with %MHC1, indicating that the influence of %MHC1 on Po/CSA and W max was due to intrinsic differences between MHC isoforms and not to concentration. The MLC3-to-MLC1 ratio was not significantly correlated with V max, V P 50, Po/CSA, or W max. These data demonstrate the powerful relationship between MHC isoforms and F- V properties of the two most common R. pipiensfiber types.

Response of slow and fast muscle to hypothyroidism: maximal shortening velocity and myosin isoforms

1992 ◽  
Vol 263 (1) ◽  
pp. C86-C94 ◽  
Author(s):  
V. J. Caiozzo ◽  
R. E. Herrick ◽  
K. M. Baldwin
Keyword(s):  
Skeletal Muscles ◽  
Relative Content ◽  
Type I ◽  
Myosin Isoforms ◽  
Velocity Data ◽  
Sprague Dawley ◽  
Shortening Velocity ◽  
Sprague Dawley Rats ◽  
Force Velocity ◽  
Fast Twitch

This study examined both the shortening velocity and myosin isoform distribution of slow- (soleus) and fast-twitch (plantaris) skeletal muscles under hypothyroid conditions. Adult female Sprague-Dawley rats were randomly assigned to one of two groups: control (n = 7) or hypothyroid (n = 7). In both muscles, the relative contents of native slow myosin (SM) and type I myosin heavy chain (MHC) increased in response to the hypothyroid treatment. The effects were such that the hypothyroid soleus muscle expressed only the native SM and type I MHC isoforms while repressing native intermediate myosin and type IIA MHC. In the plantaris, the relative content of native SM and type I MHC isoforms increased from 5 to 13% and from 4 to 10% of the total myosin pool, respectively. Maximal shortening velocity of the soleus and plantaris as measured by the slack test decreased by 32 and 19%, respectively, in response to hypothyroidism. In contrast, maximal shortening velocity as estimated by force-velocity data decreased only in the soleus (-19%). No significant change was observed for the plantaris.

Contraction of glycerinated rabbit slow-twitch muscle fibers as a function of MgATP concentration

1992 ◽  
Vol 262 (4) ◽  
pp. C1039-C1046 ◽  
Author(s):  
E. Pate ◽  
M. Lin ◽  
K. Franks-Skiba ◽  
R. Cooke
Keyword(s):  
Psoas Muscle ◽  
Isometric Tension ◽  
Maximal Velocity ◽  
Shortening Velocity ◽  
A Value ◽  
Semimembranosus Muscle ◽  
Slow Twitch Muscle ◽  
Force Velocity ◽  
Slow Twitch ◽  
Fast Twitch

We have measured the isometric tension and force-velocity relationships of glycerinated rabbit slow-twitch semimembranosus muscle as a function of MgATP concentration ([MgATP]) and have compared the results with those obtained previously from fast-twitch psoas muscle. We find that isometric tension decreases as [MgATP] increases. The magnitude of the decrease is not as great as observed in psoas. Maximum shortening velocity (Vmax) exhibits classical Michaelian saturation behavior with respect to [MgATP] with a Michaelis constant (Km) for half-maximal velocity of 18 microM and a value at saturating [MgATP] of 0.6 muscle lengths/s. Similar values were observed in fibers from soleus, another slow-twitch muscle. The corresponding values in rabbit psoas muscle are 150 microM and 1.6 lengths/s. Compared with psoas, in semimembranosus muscle Km decreases by a factor of approximately 10, whereas Vmax decreases by about a factor of 3. Thus, although in a nonphysiological regime, at low [MgATP], a "fast" muscle actually has a lower shortening velocity than a "slow" muscle.

Effects of postnatal maturation on energetics and cross-bridge properties in rat diaphragm

2002 ◽  
Vol 92 (3) ◽  
pp. 1074-1082 ◽  
Author(s):  
Gilles Orliaguet ◽  
Olivier Langeron ◽  
Belaid Bouhemad ◽  
Pierre Coriat ◽  
Yves LeCarpentier ◽  
...  
Keyword(s):  
Mechanical Efficiency ◽  
Total Force ◽  
Rat Diaphragm ◽  
Shortening Velocity ◽  
Cross Sectional ◽  
Muscle Energetics ◽  
Postnatal Maturation ◽  
Cross Bridge ◽  
Velocity Relationship ◽  
Force Velocity

The effects of maturation on cross-bridge (CB) properties were studied in rat diaphragm strips obtained at postnatal days 3, 10, and 17 and in adults (10–12 wk old). Calculations of muscle energetics and characteristics of CBs were determined from standard Huxley equations. Maturation did not change the curvature of the force-velocity relationship or the peak of mechanical efficiency. There was a significant increase in the total number of CBs per cross-sectional area (m) with aging but not in single CB force. The turnover rate of myosin ATPase increased, the duration of the CB cycle decreased, and the velocity of CBs decreased significantly only after the first week postpartum. There was a linear relationship between maximum total force and m ( r = 0.969, P < 0.001), and between maximum unloaded shortening velocity and m ( r = 0.728, P < 0.001). When this study in the rat and previous study in the hamster are compared, it appears that there are few species differences in the postnatal maturation process of the diaphragm.

Isoproterenol attenuates myosin phosphorylation and contraction of tracheal muscle

1989 ◽  
Vol 66 (5) ◽  
pp. 2017-2022 ◽  
Author(s):  
K. Obara ◽  
P. de Lanerolle
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Isometric Force ◽  
Smooth Muscles ◽  
Inhibitory Effect ◽  
Isometric Tension ◽  
Myosin Light Chain Phosphorylation ◽  
Response Curves ◽  
Shortening Velocity ◽  
Myosin Phosphorylation

The effects of isoproterenol on isometric force, unloaded shortening velocity, and myosin phosphorylation were examined in thin muscle bundles (0.1–0.2 mm diam) dissected from lamb tracheal smooth muscle. Methacholine (10(-6) M) induced rapid increases in isometric force and in phosphorylation of the 20,000-Da myosin light chain. Myosin phosphorylation remained elevated during steady-state maintenance of isometric force. The shortening velocity peaked at 15 s after stimulation with methacholine and then declined to approximately 45% of the maximal value by 3 min. Isoproterenol pretreatment inhibited methacholine-stimulated myosin light chain phosphorylation, shortening velocity, and force during the early stages of force generation. However, the inhibitory effect of isoproterenol on force and myosin phosphorylation is proportionally greater than that on shortening velocity. Isoproterenol pretreatment also caused a rightward non-parallel shift in the methacholine dose-response curves for both isometric tension and myosin light chain phosphorylation. These data demonstrate that isoproterenol attenuates the contractile properties of airway smooth muscles by affecting the rate and extent of myosin light chain phosphorylation, perhaps through a mechanism that involves the synergistic interaction of myosin light chain kinase phosphorylation and Ca2+ metabolism.

Interrelationships of contraction time, Vmax, and myosin ATPase after spinal transection

1984 ◽  
Vol 56 (6) ◽  
pp. 1594-1601 ◽  
Author(s):  
R. R. Roy ◽  
R. D. Sacks ◽  
K. M. Baldwin ◽  
M. Short ◽  
V. R. Edgerton
Keyword(s):  
Fiber Type ◽  
Biochemical Properties ◽  
Myosin Atpase ◽  
Contraction Time ◽  
Shortening Velocity ◽  
Cross Sectional ◽  
Extensor Muscles ◽  
Fast Fiber ◽  
Thoracic Cord ◽  
Fast Twitch

Interrelationships of selected mechanical and biochemical properties of hindlimb extensor muscles following low thoracic cord transection were studied. Kittens were spinalized (Sp) at 2 wk and maintained for 6–12 mo. Some Sp animals were exercised (Sp-E) on a treadmill 25–30 min/day, 5 days/wk. In situ contractile properties of the slow-twitch soleus (SOL) and fast-twitch medical gastrocnemius (MG) muscles of normal (N), Sp, and Sp-E cats were determined. Exercise did not affect most parameters; thus Sp and Sp-E groups are considered collectively. The cross-sectional areas (CSA) of the SOL and MG decreased by 43 and 32%, respectively. Specific tension (tension/CSA) was maintained in the SOL but decreased (P less than 0.05) in the MG. Contraction time (CT) and half-relaxation time were significantly shorter in the SOL but unchanged in the MG. Maximum shortening velocity (Vmax) and myosin ATPase (mumol X mg-1 X min-1) increased (P less than 0.05) in the SOL of both groups and the MG of Sp. Frequency-tension responses of both muscles shifted toward that resembling a “faster” muscle. These results substantiate the existence of relatively independent regulatory mechanisms for Vmax and CT and show that myosin ATPase levels are more closely related to Vmax than CT. Although the changes in the SOL were consistent with the hypothesis that slow fibers are converted to fast, the elevated Vmax and myosin ATPase of the MG suggest that significant changes also occur within a “fast” fiber-type category.

Comparative contractile dynamics of calling and locomotor muscles in three hylid frogs.

1995 ◽  
Vol 198 (7) ◽  
pp. 1527-1538 ◽  
Author(s):  
D McLister ◽  
E D Stevens ◽  
J P Bogart
Keyword(s):  
Relaxation Time ◽  
Isometric Tension ◽  
Hyla Versicolor ◽  
Hyla Chrysoscelis ◽  
Shortening Velocity ◽  
Call Production ◽  
Mating Call ◽  
Locomotor Muscles ◽  
Force Velocity ◽  
Isometric Twitch

Isometric twitch and tetanus parameters, force-velocity curves, maximum shortening velocity (Vmax) and percentage relaxation between stimuli (%R) across a range of stimulus frequencies were determined for a muscle used during call production (the tensor chordarum) and a locomotor muscle (the sartorius) for three species of hylid frogs, Hyla chrysoscelis, H. versicolor and H. cinerea. The call of H. chrysoscelis has a note repetition rate (NRR) approximately twice as fast as the call of H. versicolor (28.3, 42.5 and 56.8 notes s-1 for H. chrysoscelis and 14.8, 21.1 and 27.4 notes s-1 for H. versicolor at 15, 20 and 25 degrees C, respectively). Hyla cinerea calls at a very slow NRR (Approximately 3 notes s-1 at 25 degrees C). Hyla versicolor evolved from H. chrysoscelis via autopolyploidy, so the mating call of H. chrysoscelis is presumably the ancestral mating call of H. versicolor. For the tensor chordarum of H. chrysoscelis, H. versicolor and H. cinerea at 25 degrees C, mean twitch duration (19.2, 30.0 and 52.9 ms, respectively), maximum isometric tension (P0; 55.0, 94.4 and 180.5 kN m-2, respectively), tetanic half-relaxation time (17.2, 28.7 and 60.6 ms, respectively) and Vmax (4.7, 5.2 and 2.1 lengths s-1, respectively) differed significantly (P &lt; 0.05) among all three species. The average time of tetanic contraction to half-P0 did not differ significantly between H. chrysoscelis (14.5 ms) and H. versicolor (15.8 ms) but was significantly longer for H. cinerea (52.6 ms). At 25 degrees C, Vmax differed significantly among the sartorius muscles of H. chrysoscelis, H. versicolor and H. cinerea (5.2, 7.0 and 9.8 lengths s-1, respectively) but mean twitch duration (29.5, 32.2 and 38.7 ms, respectively), P0 (252.2, 240.7 and 285.1 kN m-2, respectively) and tetanic half-relaxation time (56.3, 59.5 and 60.7 ms, respectively) did not differ significantly. The average time of contraction to half-P0 did not differ significantly between H. chrysoscelis (23.7 ms) and H. versicolor (22.9 ms) but was significantly shorter for H. cinerea (15.6 ms). The only consistent contractile differences found in this study between the calling muscle and locomotor muscle of H. chrysoscelis, H. versicolor and H. cinerea were that the calling muscles generated less tension and their force-velocity relationship was much more linear. These differences may be attributable to ultrastructural differences between calling and locomotor muscles.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Force-velocity and power characteristics of rat soleus muscle fibers after hindlimb suspension

1994 ◽  
Vol 77 (4) ◽  
pp. 1609-1616 ◽  
Author(s):  
K. S. McDonald ◽  
C. A. Blaser ◽  
R. H. Fitts
Keyword(s):  
Isometric Force ◽  
Fiber Type ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Hindlimb Suspension ◽  
Type I ◽  
Shortening Velocity ◽  
Power Characteristics ◽  
Sds Page ◽  
Force Velocity

The effects of 1, 2, and 3 wk of hindlimb suspension (HS) on force-velocity and power characteristics of single rat soleus fibers were determined. After 1, 2, or 3 wk of HS, small fiber bundles were isolated, placed in skinning solution, and stored at -20 degrees C until studied. Single fibers were isolated and placed between a motor arm and force transducer, functional properties were studied, and fiber protein content was subsequently analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Additional fibers were isolated from soleus of control and after 1 and 3 wk of HS, and fiber type distribution and myosin light chain stoichiometry were determined from SDS-PAGE analysis. After 1 wk of HS, percent type I fibers declined from 82 to 74%, whereas hybrid fibers increased from 10 to 18%. Percent fast type II fibers increased from 8% in control and 1 wk of HS to 26% by 3 wk of HS. Most fibers showed an increased unloaded maximal shortening velocity (Vo), but myosin heavy chain remained entirely slow type I. The mechanism for increased Vo is unknown. There was a progressive decrease in fiber diameter (14, 30, and 38%) and peak force (38, 56, and 63%) after 1, 2, and 3 wk of HS, respectively. One week of HS resulted in a shift of the force-velocity curve, and between 2 and 3 wk of HS the curve shifted further such that Vo was higher than control at all relative loads < 45% peak isometric force. Peak absolute power output of soleus fibers progressively decreased through 2 wk of HS but showed no further change at 3 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Force-velocity properties of fatigue-resistant units in cat fast-twitch muscle after fatigue

1987 ◽  
Vol 63 (4) ◽  
pp. 1511-1518 ◽  
Author(s):  
D. D. Hatcher ◽  
A. R. Luff
Keyword(s):  
Recovery Period ◽  
Motor Units ◽  
Isometric Tension ◽  
Maximum Speed ◽  
Control Value ◽  
Force Velocity ◽  
Flexor Digitorum ◽  
Fast Twitch ◽  
Whole Muscle ◽  
Speed Of Shortening

The isometric and force-velocity properties of an identified and uniform population of fast-twitch, fatigue-resistant (FR) fibers within the flexor digitorum longus (FDL) muscle were investigated before, immediately after, and during recovery from a fatiguing repetitive isometric stimulus regime (40 Hz for 330 ms every s for 180 s) in the anesthetized cat. It was necessary to determine the smallest fraction of muscle that had the same force-velocity properties as the whole muscle. This was approximately 15% for FDL; if the fraction was less, the maximum speed of shortening was depressed and the a/Po value increased. Motor units were enlarged by partial denervation of the muscle, causing the intact motoneurons to sprout and incorporate more muscle fibers; FR units showed the greatest increase. Immediately after the fatigue regime, maximum isometric tetanic tension declined to 67% but subsequently recovered to 90% of the control value by the end of the 60-min recovery period. Maximum speed of shortening dropped to 71% of the control but after 30 min had recovered and did not differ significantly from control values. It is concluded that the capacity for recovery from fatigue is greater for FR units than for a whole muscle, which also contains fast-fatiguable units, and that the mechanisms involved in the recovery of the maximum isometric tension and maximum speed of shortening are independently regulated.

Effect of hindlimb suspension on the functional properties of slow and fast soleus fibers from three strains of mice

2003 ◽  
Vol 95 (6) ◽  
pp. 2425-2433 ◽  
Author(s):  
Julian E. Stelzer ◽  
Jeffrey J. Widrick
Keyword(s):  
Weight Bearing ◽  
Hindlimb Suspension ◽  
Type I ◽  
Shortening Velocity ◽  
Cross Sectional ◽  
Fast Fiber ◽  
Animal Strain ◽  
Slow Twitch ◽  
Fiber Atrophy ◽  
Fast Twitch

Cross-sectional area (CSA), peak Ca2+-activated force (Po), fiber specific force (Po/CSA), and unloaded shortening velocity ( Vo) were measured in slow-twitch [containing type I myosin heavy chain (MHC)] and fast-twitch (containing type II MHC) chemically skinned soleus muscle fiber segments obtained from three strains of weight-bearing and 7-day hindlimb-suspended (HS) mice. HS reduced soleus slow MHC content (from ∼50 to ∼33%) in CBA/J and ICR strains without affecting slow MHC content in C57BL/6 mice (∼20% of total MHC). Two-way ANOVA revealed HS-induced reductions in CSA, Po, and Po/CSA of slow and fast fibers from all strains. Fiber Vo was elevated post-HS, but not consistently across strains. No MHC × HS treatment interactions were observed for any variable for C57BL/6 and CBA/J mice, and the two significant interactions found for the ICR strain (CSA, Po) appeared related to inherent pre-HS differences in slow vs. fast fiber CSA. In the mouse HS models studied here, fiber atrophy and contractile dysfunction were partially dependent on animal strain and generally independent of fiber MHC isoform content.

Contractile properties of cat skeletal muscle after repetitive stimulation

1988 ◽  
Vol 64 (2) ◽  
pp. 502-510 ◽  
Author(s):  
D. D. Hatcher ◽  
A. R. Luff
Keyword(s):  
Recovery Period ◽  
Isometric Tension ◽  
Maximum Speed ◽  
Time To Peak ◽  
Force Velocity ◽  
Cross Bridges ◽  
Isometric Twitch ◽  
Flexor Digitorum ◽  
Fast Twitch ◽  
Speed Of Shortening

The isometric and force-velocity properties of the fast-twitch flexor digitorum longus (FDL) and slow-twitch soleus muscles were investigated immediately after and during recovery from a fatiguing stimulus regime (40 Hz for 330 ms every second for 180 s) in the anesthetized cat. The amplitude of the isometric twitch of FDL was unaffected but in soleus it remained depressed for much of the recovery period. Immediately after stimulation the twitch time to peak of FDL increased to 140% of the control (prefatigue) value and then reverted to control values. The maximum isometric tetanic tension (Po) developed by FDL was reduced to 67% of control values immediately after the stimulus regime, whereas soleus declined to 93% of control. Recovery of maximum force development was achieved after 45 min in FDL and after 15 min in soleus. The maximum speed of shortening of FDL was reduced to 63% of control values immediately after fatigue; despite some recovery within the first 30 min, it remained depressed during the remainder of the recovery period (up to 300 min). Maximum speed of shortening was unaltered in soleus. The a/Po value transiently increased to 176% of control values in FDL immediately after the fatigue regime but promptly returned to control values. Force-velocity properties of soleus were not affected by the stimulus regime. It is concluded that in FDL changes in the maximum speed of shortening and maximum isometric tension as a result of the stimulus regime are attributable to changes in the intrinsic behavior of cross-bridges and the metabolic status of the fibers, particularly in the fast-twitch fatigue-resistant fibers.

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