Contractile properties and myosin heavy chain composition of rat tongue retrusor musculature show changes in early adulthood after 19 days of artificial rearing

Previously, we showed that artificial rearing using the “pup in a cup” model results in decreased tongue activity and caused some minor alterations in the tongue retrusor musculature. However, the artificial rearing time frame previously chosen was brief (11 days). The purpose of the present investigation was to extend the artificial rearing period from postnatal days 3 to 21 (P21) to determine whether significant alterations occur as a result of this reduced tongue use. Several changes in contractile properties due to the artificial rearing process were observed, which fully recovered by postnatal days 41 to 42 (P41–2). These changes included a shorter twitch contraction time, shorter twitch half-relaxation time, and decreased fatigue resistance. Styloglossus muscle exhibited more neonatal myosin heavy chain (MHC) isoform at P21 for the artificially reared (AR) group. Changes that were persistent at P41–2 were also observed. Maximum tetanic tension was lower for the AR group at P21 and P41–2 compared with their dam-reared counterparts. Twitch tension was also lower by P41–2 in the AR group. At P41–2, the AR group exhibited an increase in MHC IIa and a decrease in MHC IIb for the styloglossus muscle. In addition, the AR group exhibited a decreased MHC IIb for the long head of the biceps brachii at P41–2. Our results are similar to other models of hindlimb immobilization and suspension. By extending our artificial rearing period, this reduced tongue activity induced acute changes and alterations in the tongue retrusor musculature that persisted into early adulthood.

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bHLH transcription factor MyoD affects myosin heavy chain expression pattern in a muscle-specific fashion

AJP Cell Physiology ◽

10.1152/ajpcell.2001.280.2.c408 ◽

2001 ◽

Vol 280 (2) ◽

pp. C408-C413 ◽

Cited By ~ 38

Author(s):

David J. Seward ◽

John C. Haney ◽

Michael A. Rudnicki ◽

Steven J. Swoap

Keyword(s):

Gene Expression ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Biceps Brachii ◽

Bhlh Transcription Factor ◽

Hindlimb Unweighting ◽

Protein Pool ◽

In The Wild ◽

Myod Gene ◽

Mhc Iib

A strong correlative pattern between MyoD gene expression and myosin heavy chain IIB (MHC IIB) gene expression exists. To test whether this correlative relationship is causative, MHC gene expression in muscles from MyoD(−/−) mice was analyzed. The MHC IIB gene was not detectable in the MyoD(−/−) diaphragm, whereas the MHC IIB protein made up 10.0 ± 1.7% of the MHC protein pool in the wild-type (WT) mouse diaphragm. Furthermore, the MHC IIA protein was not detectable in the MyoD(−/−) biceps brachii, and the MHC IIB protein was overexpressed in the masseter. To examine whether MyoD is required for the upregulation of the MHC IIB gene within slow muscle after disuse, MyoD(−/−) and WT hindlimb musculature was unweighted. MyoD(−/−) exhibited a diminished response in the upregulation of the MHC IIB mRNA within the soleus muscle as a result of the hindlimb unweighting. Collectively, these data suggest that MyoD plays a role in the MHC profile in a muscle-specific fashion.

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Effect of Artificial Rearing on the Contractile Properties and Myosin Heavy Chain Isoforms of Developing Rat Tongue Musculature

Journal of Neurophysiology ◽

10.1152/jn.00809.2002 ◽

2003 ◽

Vol 90 (1) ◽

pp. 120-127 ◽

Cited By ~ 14

Author(s):

Stacy A. Kinirons ◽

Mary S. Shall ◽

J. Ross McClung ◽

Stephen J. Goldberg

Keyword(s):

Myosin Heavy Chain ◽

Muscle Fiber ◽

Heavy Chain ◽

Activity Level ◽

Contractile Properties ◽

Artificial Rearing ◽

Rat Pups ◽

Decay Times ◽

Rat Tongue ◽

Developing Rat

This study's purpose was to examine the influence of an altered activity level, via artificial rearing, on the contractile properties, myosin heavy chain phenotypes (MHC), and muscle fiber sizes of the developing rat tongue retractor musculature. Artificially reared rat pups were fed through a gastric cannula, eliminating nutritive suckling from postnatal day 4 to postnatal day 14. Rat pups were observed immediately following artificial rearing (postnatal day 14) and after a 1-mo resumption of function (postnatal day 42). The contractile characteristics of the tongue retractor musculature were measured in response to stimulation of the hypoglossal nerve. At postnatal day 14, artificially reared rat pups demonstrated significantly longer twitch half-decay times, lower fusion frequencies, and a marked decrease in fatigue resistance. These contractile speed and fatigue characteristics were fully recovered following a 1-mo resumption of function. MHC phenotypes of the styloglossus muscle (a tongue retractor) were determined by gel electrophoresis. At postnatal day 14, artificial rearing had not altered the MHC phenotype or muscle fiber sizes of the styloglossus muscle. However, following a 1-mo resumption of function artificially reared rat pups demonstrated a small but significant increase in MHCIIa expression and decrease in MHCIIb expression compared with dam-reared rats. These results support artificial rearing as a useful model for altering the activity level of the tongue and suggest that normal suckling behavior is necessary for the normal postnatal development of the tongue retractor musculature. This may also be the case for premature infants necessarily fed artificially.

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Myosin heavy chain composition of single fibres from m. biceps brachii of male body builders

Acta Physiologica Scandinavica ◽

10.1111/j.1748-1716.1990.tb08989.x ◽

1990 ◽

Vol 140 (2) ◽

pp. 175-180 ◽

Cited By ~ 40

Author(s):

H. KLITGAARD ◽

M. ZHOU ◽

E. A. RICHTER

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Biceps Brachii ◽

Male Body ◽

Chain Composition ◽

Single Fibres ◽

Myosin Heavy Chain Composition

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Age-related changes in diaphragm muscle contractile properties and myosin heavy chain isoforms.

American Journal of Respiratory and Critical Care Medicine ◽

10.1164/ajrccm.150.1.8025746 ◽

1994 ◽

Vol 150 (1) ◽

pp. 174-178 ◽

Cited By ~ 45

Author(s):

L E Gosselin ◽

B D Johnson ◽

G C Sieck

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Myosin Heavy Chain Isoforms ◽

Contractile Properties ◽

Diaphragm Muscle ◽

Muscle Contractile Properties ◽

Age Related ◽

Muscle Contractile ◽

Age Related Changes

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Three-dimensional compartmentalization of myosin heavy chain and myosin light chain isoforms in dog thyroarytenoid muscle

AJP Cell Physiology ◽

10.1152/ajpcell.00323.2005 ◽

2006 ◽

Vol 290 (5) ◽

pp. C1446-C1458 ◽

Cited By ~ 14

Author(s):

Mark Bergrin ◽

Sabahattin Bicer ◽

Christine A. Lucas ◽

Peter J. Reiser

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Light Chain ◽

Myosin Light Chain ◽

Expression Patterns ◽

Shortening Velocity ◽

Single Fibers ◽

Isoform Expression ◽

Thyroarytenoid Muscle ◽

Mhc Iib

The thyroarytenoid muscle, a vocal fold adductor, has important roles in airway protection (e.g., prevention of aspiration) and phonation. Isoform expression of myosin heavy chain (MHC), a major determinant of muscle-shortening velocity, has been reported to be heterogeneous in this muscle in several mammals, differing markedly between the medial and lateral divisions. The objective was to determine the isoform expression patterns of both MHC and myosin light chain (MLC), with the latter having a modulatory role in determining shortening velocity, to further test whether the expression of both myosin subunits differs in multiple specific sites within the divisions of the dog thyroarytenoid muscle, potentially revealing even greater compartmentalization in this muscle. Our results indicate the existence of large gradients in the relative levels of individual MHC isoforms in the craniocaudal axis along the medial layer (i.e., airflow axis), where levels of MHC-I and MHC-IIA are low at both ends of the axis and high in the middle and MHC-IIB has a reciprocal distribution. The lateral layer is more uniform, with high levels of MHC-IIB throughout. The level of MHC-IID is relatively constant along the axis in both layers. Large differences exist in the distribution of MHC isoforms among single fibers isolated from sites along the craniocaudal axis, especially in the lateral layer. Systematic regional variations are apparent in the MLC isoform composition of single fibers as well, including some MLC isoform combinations that are not observed in dog limb muscles. Variations of MHC and MLC isoform expression in the dog thyroarytenoid muscle are greater than previously recognized and suggest an even broader range of contractile properties within this multifunctional muscle.

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Decreased capillarization and a shift to fast myosin heavy chain IIx in the biceps brachii muscle from young adults with spastic paresis

Journal of the Neurological Sciences ◽

10.1016/j.jns.2006.11.006 ◽

2007 ◽

Vol 253 (1-2) ◽

pp. 25-33 ◽

Cited By ~ 30

Author(s):

E.M. Pontén ◽

P.S. Stål

Keyword(s):

Young Adults ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Biceps Brachii ◽

Biceps Brachii Muscle ◽

Fast Myosin ◽

Fast Myosin Heavy Chain ◽

Spastic Paresis

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Contractile properties of motor units and expression of myosin heavy chain isoforms in rat fast-type muscle after volitional weight-lifting training

Journal of Applied Physiology ◽

10.1152/japplphysiol.00330.2016 ◽

2016 ◽

Vol 121 (4) ◽

pp. 858-869 ◽

Cited By ~ 3

Author(s):

Dawid Łochyński ◽

Dominik Kaczmarek ◽

Włodzimierz Mrówczyński ◽

Wojciech Warchoł ◽

Joanna Majerczak ◽

...

Keyword(s):

Resistance Training ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Motor Units ◽

Weight Lifting ◽

Contractile Properties ◽

Medial Gastrocnemius ◽

Maximum Force ◽

Force Frequency ◽

Contractile Characteristics

Dynamic resistance training increases the force and speed of muscle contraction, but little is known about modifications to the contractile properties of the main physiological types of motor units (MUs) that contribute to these muscle adaptations. Although the contractile profile of MU muscle fibers is tightly coupled to myosin heavy chain (MyHC) protein expression, it is not well understood if MyHC transition is a prerequisite for modifications to the contractile characteristics of MUs. In this study, we examined MU contractile properties, the mRNA expression of MyHC, parvalbumin, and sarcoendoplasmic reticulum Ca2+pump isoforms, as well as the MyHC protein content after 5 wk of volitional progressive weight-lifting training in the medial gastrocnemius muscle in rats. The training had no effect on MyHC profiling or Ca2+-handling protein gene expression. Maximum force increased in slow (by 49%) and fast (by 21%) MUs. Within fast MUs, the maximum force increased in most fatigue-resistant and intermediate but not most fatigable MUs. Twitch contraction time was shortened in slow and fast fatigue-resistant MUs. Twitch half-relaxation was shortened in fast most fatigue-resistant and intermediate MUs. The force-frequency curve shifted rightward in fast fatigue-resistant MUs. Fast fatigable MUs fatigued less within the initial 15 s while fast fatigue-resistant units increased the ability to potentiate the force within the first minute of the standard fatigue test. In conclusion, at the early stage of resistance training, modifications to the contractile characteristics of MUs appear in the absence of MyHC transition and the upregulation of Ca2+-handling genes.

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