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Soleus Muscle (soleus + muscle)
Kinds of Soleus Muscle Selected AbstractsMelatonin is as Effective as Testosterone in the Prevention of Soleus Muscle Atrophy Induced by Castration in RatsTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 4 2008Jale Öner Abstract The purpose of this experiment was to compare the weight, insulin-like growth factor-I (IGF-I) expression, and ultrastructure of the soleus muscle in growing castrated rats treated with testosterone or melatonin. In this study, adult male Wistar albino rats were used. The groups were arranged as sham, castrated, and testosterone- or melatonin-injected groups after castration. The soleus muscle samples were fixed in Bouin's solution for immunohistochemistry, and in 2.5% gluteraldehyde in 0.1 M phosphate buffer (pH 7.4). Whereas castration reduced the soleus weight and fiber diameter, testosterone and melatonin administration increased them. IGF-I immunostaining observed in the satellite cells and periphery of the myofibers was least intense in the castrated group. Strong staining of IGF-I was observed in the testosterone- and melatonin-administered groups. The ultrastructure of the soleus muscle in castrated animals showed the important ultrastructural modifications related to degeneration. In these groups, degenerative mitochondria, glycogen clusters under the sarcolemma, irregular Z lines, and loss of lamina externa were observed. The ultrastructure of myofibrils in the testosterone- and melatonin-injected groups was similar to that in sham groups in view of structure. In conclusion, we suggest that melatonin is as effective as testosterone in the prevention of atrophy induced by castration through the IGF-I axis. Anat Rec, 291:448,455, 2008. © 2008 Wiley-Liss, Inc. [source] Limitations of relaxation kinetics on muscular workACTA PHYSIOLOGICA, Issue 2 2010J. McDaniel Abstract Aim:, Positive net work produced during cyclic contractions is partially limited by relaxation kinetics, which to date, have not been directly investigated. Therefore, the purpose of this investigation was to determine the influence of relaxation kinetics on cyclic work. Methods:, Soleus muscles of four cats were isolated and subjected to a series of work loops (0.5, 1, 1.5 and 2 Hz cycle frequencies) during which stimulation terminated prior to the end of the shortening phase to allow for complete muscle relaxation and matched discrete sinusoidal shortening contractions during which stimulation remained on until the completion of the shortening phase. Muscle length changes during these protocols were centred on optimum length and were performed across muscle lengths that represented walking gait. Results:, When muscle excursions were centred on Lo relaxation kinetics decreased muscular work by 2.8 ± 0.8%, 12.1 ± 4.1%, 27.9 ± 4.5% and 40.1 ± 5.9% for 0.5, 1, 1.5 and 2 Hz respectively. However, relaxation kinetics did not influence muscular work when muscle excursions represented walking gait. In addition, muscular work produced at muscle lengths associated with walking gait was less than the work produced across Lo (55.7 ± 20.0%, 53.5 ± 21.0%, and 50.1 ± 22.0% for 0.5, 1 and 1.5 Hz respectively). Conclusion:, These results imply that relaxation kinetics are an important factor that limit the ability of muscle to produce work; however, the influence of relaxation kinetics on physiological function may depend on the relation between the optimum length and natural excursion of a muscle. [source] Gravitational unloading inhibits the regenerative potential of atrophied soleus muscle in miceACTA PHYSIOLOGICA, Issue 3 2009Y. Matsuba Abstract Aim:, The present study was performed to investigate the influence of unloading on the regeneration of atrophied and injured skeletal muscle. Methods:, Male mice (C57BL/6J), aged 8 weeks, were used. Cardiotoxin (CTX) was injected into soleus muscles bilaterally. Gravitational unloading on soleus muscle was performed by hind limb suspension for 2 weeks before and additionally 6 weeks after CTX injection in one group. Soleus muscles in the remaining groups were loaded keeping the mice in the cages and were dissected 14, 28 and 42 days after the injection. Results:, Recovery of the wet weight and protein content of soleus in the CTX-injected group was inhibited by unloading. Increase in satellite cell number, induced by CTX injection and loading, was also inhibited by unloading. Disappearance of infiltration of mononucleated cells into the necrotic area was also delayed. This phenomenon suggests that regeneration, which is indicated by the appearance of fibres with central nuclei, was inhibited by unloading. Conclusion:, Results suggested that loading plays an important role in the activation of the regenerating potential of injured skeletal muscle. [source] Role of ataxia telangiectasia mutated in insulin signalling of muscle-derived cell lines and mouse soleusACTA PHYSIOLOGICA, Issue 4 2010I. Jeong Abstract Aim:, Ataxia telangiectasia mutated (ATM) reportedly plays a role in insulin-stimulated activation of Akt in some cell types but not in others. The role of ATM in insulin signalling has not been firmly resolved for skeletal muscle cells, for which Akt phosphorylation is a pivotal step in stimulation of glucose transport. Accordingly, our aim was to determine the role of ATM in insulin effects for cell lines derived from skeletal muscle and for skeletal muscle. Methods:, We examined insulin effects in L6 myotubes, mouse soleus, C2C12 myotubes and differentiated rhabdomyosarcoma (RD) cells in the presence and absence of a low concentration (1 ,m) of the ATM inhibitor KU55933. We also compared insulin signalling in C2C12 cells expressing shRNA against ATM and control cell lines (empty vector; cells expressing non-targeting shRNA). Results:, In L6 myotubes and mouse soleus muscle, KU55933 inhibited insulin-stimulated phosphorylation of the 160 kDa substrate of Akt (AS160) despite no effect on Akt. In contrast, KU55933 prevented insulin-stimulated Akt phosphorylation in C2C12 myotubes. Furthermore, C2C12 myotubes expressing shRNA against ATM displayed reduced insulin-stimulated Akt phosphorylation compared to controls. KU55933 also decreased insulin-stimulated Akt phosphorylation in differentiated RD cells. Conclusion:, These model-dependent differences in the role of ATM in insulin action demonstrate a role of ATM in insulin-stimulated phosphorylation of Akt (in C2C12 and RD cells) but also allow the elucidation of a novel, Akt-independent role of ATM (in L6 myotubes and mouse soleus, at the level of AS160) in insulin signalling. [source] Glycogen content regulates insulin- but not contraction-mediated glycogen synthase activation in the rat slow-twitch soleus musclesACTA PHYSIOLOGICA, Issue 2 2009Y.-C. Lai Abstract Aim:, The aim of this study was to investigate the effect of glycogen content on glycogen synthase (GS) activation and phosphorylation in the slow-twitch soleus muscles after contraction, during insulin stimulation and when these two stimuli were combined. Methods:, Glycogen content was manipulated in vivo with 24 h fasting and fasting followed by 24 h refeeding. Soleus strips were electrically stimulated for 30 min in vitro, and GS activation and phosphorylation were investigated after an additional 30 min incubation with or without insulin. Results:, Fasting reduced glycogen content in soleus muscle by 40% and refeeding enhanced by 40%, compared to rats with free access to chow. Insulin-stimulated GS fractional activity was inversely correlated with glycogen content (R = ,0.95, P < 0.001, n = 24) and rate of glycogen synthesis was also inversely correlated with glycogen content (R = ,0.70, P < 0.001, n = 36). After contraction, GS fractional activity was increased to similar levels in muscles with low, normal and high glycogen content; rate of glycogen synthesis after contraction was also similar. After contraction, insulin additively increased GS activation at all glycogen contents. Group means of GS fractional activity was inversely correlated with GS Ser641 (R = ,0.93, P < 0.001) and Ser645,649,653,657 (R = ,0.85, P < 0.001) phosphorylation, but not with Ser7 phosphorylation. Conclusion:, Glycogen content regulates insulin- but not contraction-stimulated GS activation and glycogen synthesis in soleus muscles. Furthermore, phosphorylation of GS Ser641 and Ser645,649,653,657 seems to regulate GS activity in soleus. [source] Protective effects of exercise preconditioning on hindlimb unloading-induced atrophy of rat soleus muscleACTA PHYSIOLOGICA, Issue 1 2009H. Fujino Abstract Aim:, A chronic decrease in the activation and loading levels of skeletal muscles as occurs with hindlimb unloading (HU) results in a number of detrimental changes. Several proteolytic pathways are involved with an increase in myofibrillar protein degradation associated with HU. Exercise can be used to counter this increase in proteolytic activity and, thus, may be able to protect against some of the detrimental changes associated with chronic decreased use. The purpose of the present study was to determine the potential of a single bout of preconditioning endurance exercise in attenuating the effects of 2 weeks of HU on the mass, phenotype and force-related properties of the soleus muscle in adult rats. Methods:, Male Wistar rats were subjected to HU for 2 weeks. One half of the rats performed a single bout of treadmill exercise for 25 min immediately prior to the 2 weeks of HU. Results:, Soleus mass, maximum tetanic tension, myofibrillar protein content, fatigue resistance and percentage of type I (slow) myosin heavy chain were decreased in HU rats. In addition, markers for the cathepsin, calpain, caspase and ATP-ubiquitin-proteasome proteolytic pathways were increased. The preconditioning endurance exercise bout attenuated all of the detrimental changes associated with HU, and increased HSP72 mRNA expression and protein levels. Conclusion:, These findings indicate that exercise preconditioning may be an effective countermeasure to the detrimental effects of chronic decreases in activation and loading levels on skeletal muscles and that an elevation in HSP72 may be one of the mechanisms associated with these responses. [source] Gravitational unloading inhibits the regenerative potential of atrophied soleus muscle in miceACTA PHYSIOLOGICA, Issue 3 2009Y. Matsuba Abstract Aim:, The present study was performed to investigate the influence of unloading on the regeneration of atrophied and injured skeletal muscle. Methods:, Male mice (C57BL/6J), aged 8 weeks, were used. Cardiotoxin (CTX) was injected into soleus muscles bilaterally. Gravitational unloading on soleus muscle was performed by hind limb suspension for 2 weeks before and additionally 6 weeks after CTX injection in one group. Soleus muscles in the remaining groups were loaded keeping the mice in the cages and were dissected 14, 28 and 42 days after the injection. Results:, Recovery of the wet weight and protein content of soleus in the CTX-injected group was inhibited by unloading. Increase in satellite cell number, induced by CTX injection and loading, was also inhibited by unloading. Disappearance of infiltration of mononucleated cells into the necrotic area was also delayed. This phenomenon suggests that regeneration, which is indicated by the appearance of fibres with central nuclei, was inhibited by unloading. Conclusion:, Results suggested that loading plays an important role in the activation of the regenerating potential of injured skeletal muscle. [source] Androgen replacement therapy improves function in male rat muscles independently of hypertrophy and activation of the Akt/mTOR pathwayACTA PHYSIOLOGICA, Issue 4 2009C. Hourdé Abstract Aim:, We analysed the effect of physiological doses of androgens following orchidectomy on skeletal muscle and bone of male rats, as well as the relationships between muscle performance, hypertrophy and the Akt/mammalian target of rapamycin (mTOR) signalling pathway involved in the control of anabolic and catabolic muscle metabolism. Methods:, We studied the soleus muscle and tibia from intact rats (SHAM), orchidectomized rats treated for 3 months with vehicle (ORX), nandrolone decanoate (NAN) or dihydrotestosterone (DHT). Results:, Orchidectomy had very little effect on the soleus muscle. However, maximal force production by soleus muscle (+69%) and fatigue resistance (+35%) in NAN rats were both increased when compared with ORX rats. In contrast, DHT treatment did not improve muscle function. The relative number of muscle fibres expressing slow myosin heavy chain and citrate synthase activity were not different in NAN and ORX rats. Moreover, NAN and DHT treatments did not modify muscle weights and cross-sectional area of muscle fibres. Furthermore, phosphorylation levels of downstream targets of the Akt/mTOR signalling pathway, Akt, ribosomal protein S6 and eukaryotic initiation factor 4E-binding protein 1 were similar in muscles of NAN, DHT and ORX rats. In addition, trabecular tibia from NAN and DHT rats displayed higher bone mineral density and bone volume when compared with ORX rats. Only in NAN rats was this associated with increased bone resistance to fracture. Conclusion:, Physiological doses of androgens are beneficial to muscle performance in orchidectomized rats without relationship to muscle and fibre hypertrophy and activation of the Akt/mTOR signalling pathway. Taken together our data clearly indicate that the activity of androgens on muscle and bone could participate in the global improvement of musculoskeletal status in the context of androgen deprivation induced by ageing. [source] Human soleus muscle protein synthesis following resistance exerciseACTA PHYSIOLOGICA, Issue 2 2004T. A. Trappe Abstract Aim:, It is generally believed the calf muscles in humans are relatively unresponsive to resistance training when compared with other muscles of the body. The purpose of this investigation was to determine the muscle protein synthesis response of the soleus muscle following a standard high intensity bout of resistance exercise. Methods:, Eight recreationally active males (27 ± 4 years) completed three unilateral calf muscle exercises: standing calf press/heel raise, bent-knee calf press/heel raise, and seated calf press/heel raise. Each exercise consisted of four sets of 15 repetitions (,15 repetition maximum, RM, or ,70% 1RM). Fractional rate of muscle protein synthesis (FSR) was determined with a primed constant infusion of [2H5]phenylalanine coupled with muscle biopsies immediately and 3 h following the exercise in both the exercise and non-exercise (resting control) leg. Results:, FSR was elevated (P < 0.05) in the exercise (0.069 ± 0.010) vs. the control (0.051 ± 0.012) leg. Muscle glycogen concentration was lower (P < 0.05) in the exercise compared with the control leg (Decrease from control; immediate post-exercise: 54 ± 5; 3 h post-exercise: 36 ±4 mmol kg,1 wet wt.). This relatively high amount of glycogen use is comparable with previous studies of resistance exercise of the thigh (i.e. vastus lateralis; ,41,49 mmol kg,1 wet wt.). However, the exercise-induced increase in FSR that has been consistently reported for the vastus lateralis (,0.045,0.060% h,1) is on average ,200% higher than reported here for the soleus (0.019 ± 0.003% h,1). Conclusions:, These results suggest the relatively poor response of soleus muscle protein synthesis to an acute bout of resistance exercise may be the basis for the relative inability of the calf muscles to respond to resistance training programs. [source] Effects of eccentric treadmill running on mouse soleus: degeneration/regeneration studied with Myf-5 and MyoD probesACTA PHYSIOLOGICA, Issue 1 2003A.-S. Armand Abstract Aim:, The aim of this report is to show that eccentric exercise under well-controlled conditions is an alternative model, to chemical and mechanical analyses, and analyse the process of degeneration/regeneration in mouse soleus. Methods:, For this, mice were submitted to a single bout of eccentric exercise on a treadmill down a 14° decline for 150 min and the soleus muscle was analysed at different times following exercise by histology and in situ hybridization in comparison with cardiotoxin-injured muscles. Results:, We analyse the regenerative process by detection of the accumulation of transcripts coding for the two myogenic regulatory factors, Myf-5 and MyoD, which are good markers of the activated satellite cells. From 24 h post-exercise (P-E), clusters of mononucleated Myf-5/MyoD-positive cells were detected. Their number increased up to 96 h P-E when young MyoD-positive myotubes with central nuclei began to appear. From 96 to 168 h P-E the number of myotubes increased, about 10-fold, the new myotubes representing 58% of the muscle cells (168 h P-E). Conclusion:, These results show that this protocol of eccentric exercise is able to induce a drastic degeneration/regeneration process in the soleus muscle. This offers the opportunity to perform biochemical and molecular analyses of a process of regeneration without muscle environment defects. The advantages of this model are discussed in the context of fundamental and therapeutical perspectives. [source] Changes in capillary luminal diameter in rat soleus muscle after hind-limb suspensionACTA PHYSIOLOGICA, Issue 4 2000Kano This study examined the time course change of the capillary luminal diameter and the number of capillaries in the rat soleus muscle during hind-limb suspension. Male Wistar rats were divided into 1 and 3 weeks of hind-limb suspension (HS) groups (HS-1 and HS-3). The HS groups were compared with age-matched control groups. All morphometric parameters with respect to capillary and muscle fibre cross-sectional area were determined in perfusion-fixed soleus muscles. After 1 and 3 weeks of hind-limb suspension, the mean muscle fibre cross-sectional area was significantly decreased in HS-1 (,32.0%) and HS-3 (,59.3%) compared with age-matched control groups. Despite a lower capillary-to-fibre ratio (HS-1, ,19.3%; HS-3, ,21.2%), the capillary density was unchanged in HS-1 and significantly increased in HS-3 compared with age-matched control groups. The mean capillary luminal diameter was significantly smaller in HS-1 (,19.9%) and HS-3 (,21.9%) than in the age-matched control groups. The capillary-to-fibre perimeter ratio which indicates the capillary surface area available for gas exchange between blood and tissue did not significantly differ between control groups and HS groups. In conclusion, the morphometrical adaptations in rat soleus with the suspension involved changes in both the capillary luminal diameter and number of capillaries, and the change in capillary surface area was proportional to the degree of muscle atrophy in HS groups. [source] Activity alters muscle reinnervation and terminal sprouting by reducing the number of schwann cell pathways that grow to link synaptic sitesDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2003Flora M. Love Abstract In partially denervated rodent muscle, terminal Schwann cells (TSCs) located at denervated end plates grow processes, some of which contact neighboring innervated end plates. Those processes that contact neighboring synapses (termed "bridges") appear to initiate nerve terminal sprouting and to guide the growth of the sprouts so that they reach and reinnervate denervated end plates. Studies conducted prior to knowledge of this potential involvement of Schwann cells showed that direct muscle stimulation inhibits terminal sprouting following partial denervation (Brown and Holland, 1979). We have investigated the possibility this inhibition results from an alteration in the growth of TSC processes. We find that stimulation of partially denervated rat soleus muscle does not alter the length or number of TSC processes but does reduce the number of TSC bridges. Stimulation also reduces the number of TSC bridges that form between end plates during reinnervation of a completely denervated muscle. The nerve processes ("escaped fibers") that normally grow onto TSC processes during reinnervation are also reduced in length. Therefore, stimulation alters at least two responses to denervation in muscles: (1) the ability of TSC processes to form or maintain bridges with innervated synaptic sites, and (2) the growth of axons along processes extended by TSCs. © 2003 Wiley Periodicals, Inc. J Neurobiol 54: 566,576, 2003 [source] Effect of chronic denervation and denervation-reinnervation on cytoplasmic creatine kinase transcript accumulationDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2001Charles H. Washabaugh Abstract The extensor digitorum longus (EDL) and soleus muscles of adult mice were chronically denervated or denervated and allowed to reinnervate. Muscles were evaluated 1, 5, 14, 21, and 52 days after sciaticectomy. In terms of weight loss, myofiber atrophy, degeneration, and fibrosis, the soleus muscle was more affected than the EDL by chronic denervation. Fifty-two days after chronic denervation, the number of molecules of MCK/ng total RNA in both muscles (determined with competitive PCR) decreased, with the soleus muscle being more affected. At that stage, BCK mRNA levels in the denervated soleus were unchanged, but they were increased (>50%) in the EDL. Reinnervation restored MCK transcript accumulation in the EDL, whereas, in the soleus MCK, transcripts exceeded control values by 57%, approaching levels in the reinnervated EDL. Despite restoration of MCK mRNA levels, the number of molecules of BCK mRNA/ng total RNA was four- to fivefold higher in reinnervated versus control muscles, suggesting that the genes encoding the CK mRNAs are not coordinately regulated in adult muscle. The role of denervation induced, fiber type changes in regulating CK mRNA accumulation has been evaluated. Electron microscopic analyses have established that fibrosis is not a factor that determines BCK mRNA levels in the chronically denervated or denervated-reinnervated muscles. CK isozyme analyses support the hypothesis that a greater proportion of BCK mRNA found in 52 day chronically denervated and denervated-reinnervated muscles is produced in myofibers vs. nonmuscle cells than in control muscles. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 194,206, 2001 [source] Transection of the sciatic nerve and reinnervation in adult rats: muscle and endplate morphologyEQUINE VETERINARY JOURNAL, Issue S33 2001J. IJKEMA-PAASSEN Summary The functional recovery after peripheral nerve lesions is generally poor. We studied whether changes in muscles after reinnervation might explain such disappointing results. The functional recovery after peripheral nerve lesions is generally poor. Changes in muscle morphology and neuromuscular innervation might partly explain this lack of compensation. In order to test this hypothesis, we studied muscular differentiation in the soleus, gastrocnemius and tibialis anterior muscles at 7, 15 and 21 weeks after a sciatic nerve lesion in adult rats. In the gastrocnemius and tibialis muscles the percentages of type II muscles fibres were decreased at 7 and 15 weeks but at 21 weeks they again approached normal values. The soleus muscle, however, was permanently decreased in size and this muscle, in contrast to the normal soleus muscle, contained mainly type II fibres. The morphology of the endplates showed distinct stages of degeneration and reinnervation. Two weeks after denervation, in rats in which reinnervation was prevented, all 3 muscles contained considerable numbers of morphologically abnormal endplates and, after 7 weeks, no endplates were detected. During reinnervation, endplates showing signs of acetylcholinesterase activity were observed in all 3 muscles from 7 weeks. At later ages a shift towards morphologically normal endplates occurred, but complete recovery was not observed. Endplates in all 3 muscles were polyneurally innervated at 7 weeks. Although these percentages decreased over age, polyneural innervation was still present at 21 weeks. We conclude that the changes in the distribution of fibre types, abnormal endplate morphology and polyneural innervation may in part explain the poor functional recovery after peripheral nerve lesions. [source] Osteomyocutaneous peroneal artery perforator flap for reconstruction of composite maxillary defects,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 4 2006Sukru Yazar MD Abstract Background. Composite maxillary defects often involve the maxilla, nasal mucosa, palate, and maxillary sinus. We presented the surgical techniques and outcome of the osteomyocutaneous peroneal artery perforator (PAP) flap for reconstruction of composite maxillary defects. Methods. Six patients underwent an osteomyocutaneous PAP flap reconstruction of composite maxillary defects. The average age was 52 years. The defects were Cordeiro type II in three patients and type IV midfacial defects in another three patients. Results. No total or partial flap failures occurred. At a mean 12-month follow-up, five patients had a normal speech and were able to eat a regular diet. One patient tolerated a soft diet and had intelligible speech. One patient had ectropion develop. Excellent cosmesis was found in five patients. Conclusions. The osteomyocutaneous PAP flap represents a further refinement of the fibula flap and increases its versatility, with multiple skin paddles, bone segments, and soleus muscle independently isolated. It is a comparable reconstruction option for composite maxillary defects. © 2005 Wiley Periodicals, Inc. Head Neck28: 297,304, 2006 [source] An unusual cause of calf hypertrophy: severe lumbar canal stenosis with S1 nerve root radiculopathyINTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 4 2007V. ONG Abstract We report an unusual case of calf hypertrophy in a 62-year-old woman who developed progressive enlargement of the left calf in association with chronic lower back pain. Magnetic resonance imaging (MRI) of the affected calf confirmed enlargement of the soleus muscle. MRI of the lumbar spine showed multilevel degenerative changes. Electromyography revealed neurogenic features consistent with S1 radiculopathy. Our case illustrates that muscular hypertrophy may follow chronic denervation as a consequence of spinal neural compressive disease. The various mechanisms postulated for this distinct condition and therapeutic strategies are outlined. [source] Differential activation of stress-responsive signalling proteins associated with altered loading in a rat skeletal muscleJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2005Inho Choi Abstract Skeletal muscle undergoes a significant reduction in tension upon unloading. To explore intracellular signalling mechanisms underlying this phenomenon, we investigated twitch tension, the ratio of actin/myosin filaments, and activities of key signalling molecules in rat soleus muscle during a 3-week hindlimb suspension and 2-week reloading. Twitch tension and myofilament ratio (actin/myosin) gradually decreased during unloading but progressively recovered to initial levels during reloading. To study the involvement of stress-responsive signalling proteins during these changes, the activities of protein kinase C alpha (PKC,) and three mitogen-activated protein kinases (MAPKs),c-Jun NH2 -terminal kinase (JNK), extracellular signal-regulated protein kinase (ERK), and p38 MAPK,were examined using immunoblotting and immune complex kinase assays. PKC, phosphorylation correlated positively with the tension (Pearson's r,=,0.97, P,<,0.001) and the myofilament ratio (r,=,0.83, P,<,0.01) over the entire unloading and reloading period. Treatment of the soleus muscle with a PKC activator resulted in a similar paralleled increment in both PKC, phosphorylation and the ,-sarcomeric actin expression. The three MAPKs differed in the pattern of activation in that JNK activity peaked only for the first hours of reloading, whereas ERK and p38 MAPK activities remained elevated during reloading. These results suggest that PKC, may play a pivotal role in converting loading stress to intracellular changes in contractile proteins that determine muscle tension. Differential activation of MAPKs may also help alleviate muscle damage, modulate energy transport and/or regulate the expression of contractile proteins upon altered loading. J. Cell. Biochem. © 2005 Wiley-Liss, Inc. [source] Significant differences in proton trimethyl ammonium signals between human gastrocnemius and soleus muscleJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2004Jiani Hu PhD Abstract Purpose To study the apparent heterogeneous characteristics of trimethyl ammonium (TMA) in healthy human muscles at rest, and to illustrate the importance of establishing the baseline characteristics of proton metabolites in muscles with a West Nile patient. Materials and Methods Point-resolved spectroscopy (PRESS) magnetic resonance spectroscopy imaging (MRSI) with lipid suppression and optional outer-volume presaturation were used to acquire 1H spectra of human muscles at rest at 1.5 Tesla. A total of 28 subjects (27 normal volunteers and 1 patient with West Nile disease) between the ages of 22 and 76 participated in the study. Results The apparent T2 values of TMA for soleus and gastrocnemius muscles in normal volunteers are 180 ± 50 and 80 ± 20 msec, respectively. This difference has profound effects on the apparent spectral pattern of 1H metabolites. The TMA/total creatine (tCr) spectral pattern of the soleus muscle of a West Nile patient resembles that of gastrocnemius muscle of healthy volunteers. Conclusion There are significant differences in the apparent T2 values of TMA between healthy soleus and gastrocnemius muscles at rest. It is important to establish the baseline characteristics of proton metabolites before clinical or physiological studies can be performed. J. Magn. Reson. Imaging 2004;19:617,622. © 2004 Wiley-Liss, Inc. [source] Site-specific detection of S -nitrosylated PKB ,/Akt1 from rat soleus muscle using CapLC-Q-TOFmicro mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2005Xiao-Ming Lu Abstract Protein Kinase B,(PKB,, or Akt1) is believed to play a crucial role in programmed cell death, cancer progression and the insulin-signaling cascade. The protein is activated by phosphorylation at multiple sites and subsequently phosphorylates and activates eNOS. Free cysteine residues of the protein may capture reactive, endogenously produced nitric oxide (NO) as S -nitrosothiols. Site-specific detection of S -nitrosylated cysteine residues, usually at low stoichiometry, has been a major challenge in proteomic research largely due to the lack of mass marker for S -nitrosothiols that are very labile under physiologic conditions. In this report we describe a sensitive and specific MS method for detection of S -nitrosothiols in PKB ,/Akt1 in rat soleus muscle. PKB ,/Akt1 was isolated by immunoprecipitation and 2D-gel electrophoresis, subjected to in-gel tryptic digestion, and cysteinyl nitrosothiols were reacted with iodoacetic acids [2-C12/C13 = 50/50] under ascorbate reduction conditions. This resulted in the production of relatively stable carboxymethylcysteine (CMC) immonium ions (m/z 134.019 and m/z 135.019) within a narrow argon collision energy (CE = 30 ± 5 V) in the high MS noise region. In addition, free and disulfide-linked cysteine residues were converted to carboxyamidomethylcysteines (CAM). Tryptic S -nitrosylated parent ion was detected with a mass accuracy of 50 mDa for the two CMC immonium ions at the triggered elution time during capillary liquid chromatography (LC) separation. A peptide containing Cys296 was discriminated from four co-eluting tryptic peptides under lock mass conditions (m/z 785.8426). S -nitrosothiol in the tryptic peptide, ITDFGLBKEGIK (B: CAM, [M + 2H]2+ = 690.86, Found: 690.83), is believed to be present at a very low level, since the threshold for the CMC immonium trigger ions was set at 3 counts/s in the MS survey. The high levels of NO that are produced under stress conditions may result in increased S -nitrosylation of Cys296 which blocks disulfide bond formation between Cys296 and Cys310 and suppresses the biological effects of PKB ,/Akt1. With the procedures developed here, this process can be studied under physiological and pathological conditions. Copyright © 2005 John Wiley & Sons, Ltd. [source] Comparative study between the effect of the peroxisome proliferator activated receptor-, ligands fenofibrate and n-3 polyunsaturated fatty acids on activation of 5,-AMP-activated protein kinase-,1 in high-fat fed ratsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2009Tarek M. Kamal Motawi Abstract Objectives Obesity is a risk factor for type 2 diabetes mellitus. It results from an energy imbalance in which energy intake exceeds energy expenditure. The cellular fuel gauge 5,-AMP-activated protein kinase (AMPK) is a heterotrimeric protein consisting of one catalytic subunit (,) and two non-catalytic subunits (, and ,), and approximately equal levels of ,1 and ,2 complexes are present in the liver. AMPK regulates metabolic pathways in response to metabolic stress and in particular ATP depletion to switch on energy-producing catabolic pathways such as ,-oxidation of fatty acids and switch off energy-depleting processes such as synthesis of fatty acid and cholesterol. A high-fat diet alters AMPK-,1 gene expression in the liver and skeletal muscle of rats and results in body weight gain and hyperglycaemia. The aim of this study was to investigate and compare the potential effects of peroxisome proliferator-activated receptor (PPAR)-, agonists fenofibrate and n-3 polyunsaturated fatty acids (PUFAs) in modulation of AMPK-,1 activity in liver and skeletal muscle of high-fat diet fed rats. Methods Reverse transcription,polymerase chain reaction was used for determination of AMPK-,1 in liver and soleus muscle and both PPAR-, and CPT-1 in hepatic tissues. Serum, total cholesterol, triacylglycerol, fatty acid and fasting blood glucose were determined colorimetrically. Key findings Both PPAR-, agonists, fenofibrate and n-3 PUFA, increased the mRNA expression of AMPK-,1 activity in liver and skeletal muscle of obese diabetic rats. Fenofibrate was superior in its activation of hepatic mRNA expression of AMPK-, 1 to exert more lipolytic effect and body weight reduction, as estimated through the decrease of triacylglycerol output and serum levels of fatty acid on the one hand and the increase in CPT-1 mRNA expression, the key enzyme in ,-oxidation of fatty acid, on the other hand. n-3 PUFA activated AMPK-,1 mRNA expression in skeletal muscle much more than fenofibrate to reveal more hypoglycaemic effect. Conclusions The PPAR-, agonists fenofibrate and n-3 PUFA could efficiently activate AMPK-,1 mRNA expression in liver and skeletal muscle to exert body weight reduction and hypoglycaemic effect, respectively. [source] Acute Alcohol Intoxication Increases REDD1 in Skeletal MuscleALCOHOLISM, Issue 5 2008Charles H. Lang Background:, The mechanism by which acute alcohol (EtOH) intoxication decreases basal muscle protein synthesis via inhibition of the Ser/Thr kinase mammalian target of rapamycin (mTOR) is poorly defined. In this regard, mTOR activity is impaired after over expression of the regulatory protein REDD1. Hence, the present study assessed the ability of REDD1 as a potential mediator of the EtOH-induced decrease in muscle protein synthesis. Methods:, The effect of acute EtOH intoxication on REDD1 mRNA and protein was determined in striated muscle of rats and mouse myocytes using an RNase protection assay and Western blotting, respectively. Other components of the mTOR signaling pathway were also assessed by immunoblotting. For comparison, REDD1 mRNA/protein was also determined in the muscle of rats chronically fed an alcohol-containing diet for 14 weeks. Results:, Intraperitoneal (IP) injection of EtOH increased gastrocnemius REDD1 mRNA in a dose- and time-dependent manner, and these changes were associated with reciprocal decreases in the phosphorylation of 4E-BP1, which is a surrogate marker for mTOR activity and protein synthesis. No change in REDD1 mRNA was detected in the slow-twitch soleus muscle or heart. Acute EtOH produced comparable increases in muscle REDD1 protein. The EtOH-induced increase in gastrocnemius REDD1 was independent of the route of EtOH administration (oral vs. IP), the nutritional state (fed vs. fasted), gender, and age of the rat. The nonmetabolizable alcohol tert -butanol increased REDD1 and the EtOH-induced increase in REDD1 was not prevented by pretreatment with the alcohol dehydrogenase inhibitor 4-methylpyrazole. In contrast, REDD1 mRNA and protein were not increased in the isolated hindlimb perfused with EtOH or in C2C12 myocytes incubated with EtOH, under conditions previously reported to decrease protein synthesis. Pretreatment with the glucocorticoid receptor antagonist RU486 failed to prevent the EtOH-induced increase in REDD1. Finally, the EtOH-induced increase in REDD1 was not associated with altered formation of the TSC1,TSC2 complex or the phosphorylation of TSC2 which is down stream in the REDD1 stress response pathway. In contradistinction to the changes observed with acute EtOH intoxication, REDD1 mRNA/protein was not changed in gastrocnemius from chronic alcohol-fed rats despite the reduction in 4E-BP1 phosphorylation. Conclusions:, These data indicate that in fast-twitch skeletal muscle (i) REDD1 mRNA/protein is increased in vivo by acute EtOH intoxication but not in response to chronic alcohol feeding, (ii) elevated REDD1 in response to acute EtOH appears due to the production of an unknown secondary mediator which is not corticosterone, and (iii) the EtOH-induced decrease in protein synthesis can be dissociated from a change in REDD1 suggesting that the induction of this protein is not responsible for the rapid decrease in protein synthesis after acute EtOH administration or for the development of alcoholic myopathy in rats fed an alcohol-containing diet. [source] Suppression of the human spinal H-reflex by propofol: a quantitative analysisACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2006J. H. Baars Background:, The spinal cord is an important site of anaesthetic action because it mediates surgical immobility. During anaesthesia with volatile anaesthetics, it has been shown that the suppression of the spinal H-reflex correlates with surgical immobility. To evaluate whether the H-reflex could also be a possible candidate for monitoring immobility during propofol anaesthesia, this study assessed the concentration-dependent suppression of the H-reflex by propofol. To discriminate different effect sites, the individual concentration response-curves and the t1/2ke0 of the H-reflex have been compared with those of two EEG parameters. Methods:, In 18 patients, anaesthesia was induced and maintained with propofol infused using a target-controlled infusion pump at stepwise increasing and decreasing plasma concentrations between 0.5 and 4.5 mg/l. The H-reflex of the soleus muscle was recorded at a frequency of 0.1 Hz. Calculated propofol concentrations and H-reflex amplitude were analysed in terms of a pharmacokinetic-pharmacodynamic (PKPD) model with a sigmoid concentration-response function. Results:, For slowly increasing propofol concentrations, computer fits of the PKPD model for H-reflex suppression by propofol yielded the following median parameters: EC50 1.1 (0.8,1.7) mg/l, slope parameter 2.4 (2.0,3.7), and a t1/2ke0 of 6.7 (2.8,7.5, 25,75% quantiles) min. For the bispectral index, the t1/2ke0 was 2.2 (1.8,3.1) min and for the spectral edge frequency at the 95th percentile of the power spectrum 2.8 (1.9,3.2) min. Conclusions:, Propofol, unlike sevoflurane, suppresses the spinal H-reflex at concentrations far lower than the C50 skin incision. The differences in t1/2ke0 -values indicate the presence of different effect compartments for effects on the H-reflex and the EEG. [source] MRI of muscular fatMAGNETIC RESONANCE IN MEDICINE, Issue 4 2002Fritz Schick Abstract An MRI technique with high selectivity and sensitivity to the signal components in the chemical shift range of methylene and methyl protons of fatty acids has been developed for noninvasive assessment of muscular fat in vivo. A spoiled gradient-echo sequence with spatial-spectral excitation by six equidistant pulses with 2°-(,9°)-17°-(,17°)-9°-(,2°) and a multi-echo train (TE = 16, 36, 56, 76, 96, and 116 ms) allowed a series of images to be recorded with a receiver bandwidth of 78 Hz per pixel. SIs from phantoms with lipid contents between 0.1% and 100% were compared to those from pure water. Thirty healthy volunteers underwent fat-selective imaging of their lower leg, and parallel localized proton spectroscopy of the tibialis anterior and the soleus muscle by a single-voxel stimulated echo acquisition mode (STEAM) technique (TR = 2 s, TE = 10 ms, TM = 15 ms). Results show a high correlation (r = 0.91) between fat imaging and the spectroscopic approach in the soleus muscle, considering the percentage total fat content of musculature. The correlation coefficient was clearly lower (r = 0.55) in the tibialis anterior muscle due to signal contaminations from adjacent subcutaneous fat in the images, inhomogeneous fat distribution, and generally lower lipid content in this muscle. Applications of the new imaging technique showed marked intra- and interindividual variability in the spatial distribution of lipids in the musculature of the lower leg. No significant correlation of the muscular fat with the thickness of the subcutaneous fat layer was found. In addition, the body mass index does not appear to determine muscular fat content, except in very obese cases. Magn Reson Med 47:720,727, 2002. © 2002 Wiley-Liss, Inc. [source] Combined peroneal and proximal tibial nerve palsies,MICROSURGERY, Issue 4 2009Eric H. Williams M.D. Combined compression of both the common peroneal nerve and the proximal tibial nerve at the level of the popliteal fossa is rare. Recently, an anatomic site of compression of the proximal tibial nerve at the soleal sling (originating arch for the soleus muscle) has been described in cadavers. The present report includes three patients who had a combined compression of the common peroneal nerve at the fibular neck (fibular tunnel syndrome) and compression of the proximal tibial nerve at the soleal sling (soleal sling syndrome). In each case, blunt trauma was the precipitating event. Neurolysis of both nerves resulted in restoration of motor and sensory function in each ofthese three patients. This is the first clinical report illustrating combined neurolysis of the common peroneal at the knee and the proximal tibial nerve in the soleal sling. © 2009 Wiley-Liss, Inc. Microsurgery, 2009. [source] Anatomic study and clinical application of distally-based neuro-myocutaneous compound flaps in the legMICROSURGERY, Issue 6 2007Ai-Xi Yu M.D., Ph.D. Objective: Anatomical study on the anastomosis between the neurovascular axis and the musculocutaneous perforators in leg. The distally-based neuron-myocutaneous flap was used for repairing special patients with soft tissue defect in foot and ankle. Methods: Systematical observation was carried out on 30 injected lower legs about the anastomosis between the neurovascular axis and the musculocutaneous perforators, and we summarized the clinical experiences from February 2004 on 12 cases using distally-based neuron-myocutaneous flap for repairing special patients with soft tissue defect in foot and ankle. Results: The neuron-vessels of sural nerve anastomosed permanently with the musculocutaneous perforators of medial and lateral head of gastrocnemius. There were two to three anastomoses found, respectively. The medial anastomotic branches were found larger in caliber than the lateral ones. The spatium intermuscular branches of the posterior tibial artery gave off their junior branches and anastomosed with the vessels in or out of the soleus muscle. There were two to three muscular branches perforated out of the soleus muscle, with mean caliber 0.5 ± 0.2 mm and accompanying with one to two veins. The neuron-vessels of the superficial fibular nerve gave off alone its course two to three muscular branches to the long extensor muscle digits and the long fibular muscle, and one to two fasciocutaneous to the skin. The diameter of the muscular branches was 0.4 ± 0.2 mm in average. Accounting for the operating models in the 12 cases, we had distally-based sural neuron-myocutaneous flap in 7 cases, saphenous neuron-myocutaneous flap in 4 cases, and superficial fibular neuron-myocutaneous flap in 1 case. All these cases were followed up at least for 2,6 months and had the significant results of nice limb's shape and cured osteomyelitis. Conclusion: Distally-based neuro-myocutaneous flap in leg can live with reliable blood circulation. These flaps offer excellent donor sites for repairing special the soft tissue defect in foot and ankle. © 2007 Wiley-Liss, Inc. Microsurgery, 2007. [source] Soleus H-reflex inhibition during gait initiation in Parkinson's diseaseMOVEMENT DISORDERS, Issue 7 2005Koichi Hiraoka PT Abstract The soleus H-reflex excitability during gait initiation was investigated in Parkinson's disease. Eleven patients participated in this study. Patients stepped forward as soon as the start signal flashed. Soleus H-reflex was evoked from the trailing leg 100, 300, or 600 msec after the start signal. The electromyographic activity in the soleus muscle immediately before evoking the H-reflex and the ankle joint motion were recorded. The soleus H-reflex was inhibited 300 msec after the start signal. The amount of the soleus H-reflex inhibition was inversely correlated with the Hoehn and Yahr stage; Items 14, 29, and 31 of the Unified Parkinson's Disease Rating Scale; and the delay of the onset of the ankle dorsiflexion from the start signal. In contrast, the amount of electromyographic activity immediately before evoking the H-reflex was not significantly correlated with those measures but was significantly correlated with Item 22 of the Unified Parkinson's Disease Rating Scale. Those findings indicate that the amount of soleus H-reflex inhibition during gait initiation depends on the severity of the disease. Abnormality of descending command may be related to the severity-dependent H-reflex inhibition. © 2005 Movement Disorder Society [source] Modulation of the soleus H-reflex following galvanic vestibular stimulation and cutaneous stimulation in prone human subjectsMUSCLE AND NERVE, Issue 2 2009Catherine R. Lowrey MSc Abstract There is evidence to suggest that vestibular and somatosensory inputs may interact when they are processed by the central nervous system, although the nature of the individual sensory contributions to this interaction is unknown. We examined the effects of a combined vestibular and cutaneous conditioning stimulus on the motoneuron pool that supplies the soleus muscle via the Hoffman reflex (H-reflex). We applied galvanic vestibular stimulation (GVS; bipolar, binaural, 500 ms, 2.5-mA square-wave pulse) and cutaneous stimulation (medial plantar nerve; 11 ms, three-pulse train, 200 HZ) to prone human subjects and examined changes in the amplitude of the H-reflex. GVS alone caused facilitation (approximately 20%) of the H-reflex, whereas ipsilateral cutaneous stimulation alone caused a 26% inhibition. Paired GVS and cutaneous stimulation resulted in a linear summation of the individual conditioning effects. H-reflex amplitudes observed after paired conditioning with GVS and cutaneous stimulation could be predicted from the amplitudes observed with individual conditioning. These results suggest that in the prone position, when the muscles are not posturally engaged, vestibular and somatosensory information appear to sum in a linear fashion to influence the reflex response of lower limb motoneurons. Muscle Nerve 40: 213,220, 2009 [source] Gene and protein expression associated with protein synthesis and breakdown in paraplegic skeletal muscleMUSCLE AND NERVE, Issue 4 2008Micah J. Drummond PhD Abstract Spinal cord injury reduces the rate of skeletal muscle protein synthesis and increases protein breakdown, resulting in rapid muscle loss. The purpose of this study was to determine whether long-term paraplegia would eventually result in a downregulation of muscle mRNA and protein expression associated with both protein synthesis and breakdown. After 10 weeks of spinal cord transection, soleus muscle from 12 rats (6 sham-control, 6 paraplegic) was studied for mRNAs and proteins associated with protein synthesis and breakdown using real-time polymerase chain reaction and immunoblotting techniques. Protein kinase B (PKB/Akt), ribosomal S6 kinase 1 (S6K1), and myogenin mRNA were downregulated, whereas muscle ring finger 1 (MuRF1) and phospho-forkhead transcription factor 4 (FoxO4) protein were increased in paraplegic rats. We conclude that gene and protein expression of pathways associated with protein synthesis are reduced, whereas some markers of protein breakdown remain elevated following chronic paraplegia. Clinical interventions designed to increase muscle protein synthesis may be helpful in preventing excessive muscle loss during long-term paraplegia. Muscle Nerve, 2008 [source] Inactivity-induced modulation of Hsp20 and Hsp25 content in rat hindlimb musclesMUSCLE AND NERVE, Issue 1 2004Kimberly A. Huey PhD Abstract Denervation decreases small heat shock protein (HSP) content in the rat soleus muscle; however, it is unknown whether this change is due to inactivity or absence of a nerve,muscle connection. Spinal cord isolation (SI) is a model of inactivity with an intact neuromuscular connection. After 7 days of SI, Hsp20 and Hsp25 levels in the soleus, plantaris, and adductor longus muscles were lower than in control rats, whereas Hsp20 was unchanged and Hsp25 increased in the tibialis anterior. The results for the soleus indicate that these small HSPs respond to inactivity and that this response is not influenced by neural activity,independent factors. Furthermore, the data indicate that these HSPs are impacted to a greater degree in muscles that are predominantly slow or have an antigravity function than in flexor muscles. Understanding the regulation of these HSPs during chronic reductions in neuromuscular activity may have valuable applications for conditions such as spinal cord injury. Muscle Nerve 30: 95,101, 2004 [source] Dynamic contrast-enhanced MRI of muscle perfusion combined with MR angiography of collateral artery growth in a femoral artery ligation modelNMR IN BIOMEDICINE, Issue 8 2007Quido G. de Lussanet Abstract To assess the use of MRI for evaluating changes in muscle blood flow and number of collateral arteries, serial dynamic contrast-enhanced MRI (DCE-MRI) was combined with high-spatial-resolution contrast-enhanced MR angiography (MRA) in a peripheral ischemia model. The combined MRI (DCE-MRI and MRA) protocol was performed serially in 15 male rabbits at 2,h (day 0+), 7 days, and 21 days after femoral artery ligation. In the anterior tibial and soleus muscle, changes in resting muscle blood flow determined as the endothelial transfer coefficient (Ktrans) and arterial inflow delay from DCE-MRI and changes in the number of sub-millimeter sized collateral arteries as scored with MRA were measured. Directly after ligation, Ktrans in the anterior tibial muscle was reduced to 23% of that in the control limb, then recovered to 81% on day 7, and to 85 % on day 21. Ktrans in the soleus muscle recovered from a reduction to 63% on day 0+, to 85% on day 7, and to 90% on day 21. The number of collaterals around the ligated femoral artery increased from 1.1 on day 0+ to 4.2 on day 7, and 6.0 on day 21 in the ligated limb only. Combined DCE-MRI and MRA allows non-invasive serial monitoring of changes in muscle blood flow and growth of sub-millimeter sized collateral arteries in a rabbit femoral artery ligation model. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||||||||