Salbutamol changes the molecular and mechanical properties of canine skeletal muscle.

Zhang, K M; Hu, Ping; Wang, S W; Feher, Joseph; Wright, Leon D.; Wechsler, Andrew S.; Spratt, John A.; Briggs, F. Norman

doi:10.1113/jphysiol.1996.sp021678

Cited by 26 publications

(38 citation statements)

References 37 publications

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“…Our finding of three MHC isoforms is consistent with the results of Zhang et al [1996] who demonstrated three isoforms with SDS-polyacrylamide gel electrophoresis in the vastus intermedius and latissimus dorsi muscles of dogs. Though fibres only expressing the MHCIIx isoform were not found during the present study, this isoform might be more abundantly expressed in other canine muscles, especially in those involved in more phasic contractions.…”

Section: Discussionsupporting

confidence: 82%

Pattern of Myosin Heavy Chain Isoforms in Different Fibre Types of Canine Trunk and Limb Skeletal Muscles

Štrbenc¹,

Smerdu²,

Zupanc³

et al. 2004

Cells Tissues Organs

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The aim of this study was to determine the pattern of myosin heavy chain (MHC) isoform expressions within the muscle fibres of functionally diverse trunk and limb dog muscles using monoclonal antibodies that are specific to MHC isoforms. We found that three MHC isoforms are expressed in dog skeletal muscles. The pattern of their expressions determined the existence of ‘pure’ fibres, i.e. I and IIa, both expressing only one MHC isoform, and ‘hybrid’ fibres, i.e. I/IIa and IIa/x, that co-expressed two MHC isoforms. While the MHCI, MHCIIa and MHCI/IIa fibres corresponded to the myofibrillar ATPase type fibres I, IIA and IIC, respectively, the hybrid MHCIIa/x fibres mostly behaved like the IIDog fibre type in myofibrillar ATPase reaction as described by Latorre et al. [J Anat 1993a;182:329–337]. No pure MHCIIx fibres were found. Though MHCIIa/x fibres were quite numerous, their presence varied not only within different muscles but within the same muscle of different animals as well. We suggest that the discrepancies in the classification of fibre types according to their myofibrillar ATPase activity between different studies of dog skeletal muscles are probably a consequence of the variable content of the MHCIIa and MHCIIx isoforms in the MHCIIa/x hybrid fibres. Estimating the histochemical metabolic profile of fibres we found that in all fast fibres oxidative-glycolytic metabolism prevailed, whereas in slow fibres oxidative metabolism was more pronounced.

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Section: Discussionsupporting

confidence: 82%

Pattern of Myosin Heavy Chain Isoforms in Different Fibre Types of Canine Trunk and Limb Skeletal Muscles

Štrbenc¹,

Smerdu²,

Zupanc³

et al. 2004

Cells Tissues Organs

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“…MHC-I, -IIa and -IIx, are expressed in canine skeletal muscles [Štrbenc et al, 2004]. In the present study, using SDS-PAGE combined with the immunoblotting technique, we confi rmed our previous fi ndings and the assumptions that only two fast MHC isoforms are expressed in large canine skeletal muscles and that they correspond to MHC-IIa and -IIx of rats [Amann and Fraga, 1992;Amann et al, 1993;Zhang et al, 1996]. To our knowledge, this is the fi rst study of canine skeletal muscles in which electrophoretic MHC isoform bands were identifi ed by the immunoblotting technique.…”

Section: Discussionsupporting

confidence: 78%

Identification of Myosin Heavy Chain I, IIa and IIx in Canine Skeletal Muscles by an Electrophoretic and Immunoblotting Study

Smerdu¹,

Štrbenc

Meznarič³

et al. 2005

Cells Tissues Organs

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To determine which myosin heavy chain (MHC) isoforms are expressed in canine skeletal muscles, different muscle samples of five mixed-breed dogs were analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The separated MHC isoforms were identified by immunoblotting technique using a set of specific monoclonal antibodies. To compare the results of the electrophoretic and immunoblotting study, the pattern of MHC isoform expression and histochemical profiles of canine fibres were additionally demonstrated on serial muscle sections by immunohistochemistry and myofibrillar adenosine triphosphatase (mATPase) histochemistry. Not more than three MHC isoforms were demonstrated by SDS-PAGE in the analysed canine muscles. By the immunoblotting technique, the fastest migrating MHC band was identified as slow or MHC-I, the intermediate one as MHC-IIx and the slowest migrating band as MHC-IIa isoform. Since none of the three MHC bands and none of the analysed fibres were recognized by the antibody specific to MHC-IIb of rats, we concluded that MHC-IIb is not expressed in large skeletal muscles of dogs. Similarly, only three major fibre types, i.e. I, IIA and IIX, were revealed according to the pattern of MHC immunohistochemistry and mATPase reaction. Type IIA fibres were more alkali- and acid-stable than type IIX fibres after mATPase histochemistry; hence, the latter corresponded to type IIDog fibres. However, beside the three major fibre types, scarce hybrid fibres co-expressing two MHC isoforms (I/IIA and IIA/IIX) were demonstrated by immunohistochemistry.

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“…It has been shown previously that treatment with the ␤ 2 -agonist salbutamol for 6 wk increased SERCA1 protein levels in canine latissimus dorsi and vastus intermedius muscles (36). Similarly, our findings show that fenoterol treatment increased SERCA1 protein levels in the RG and WG muscle of both adult and aged rats.…”

Section: Discussionsupporting

confidence: 74%

“…However, the mechanisms responsible for this change in contractility have not been elucidated. It has been demonstrated that a 6-wk administration of the ␤ 2 -agonist salbutamol can reduce contraction time in canine skeletal muscle (36). Salbutamol treatment also increased the rate of SR Ca 2ϩ resequestration, which suggested that changes in skeletal muscle contractile parameters were mediated by alterations in SR proteins, namely a ␤ 2 -agonist-mediated induction of SERCA1 protein levels (36).…”

mentioning

confidence: 99%

“…It has been demonstrated that a 6-wk administration of the ␤ 2 -agonist salbutamol can reduce contraction time in canine skeletal muscle (36). Salbutamol treatment also increased the rate of SR Ca 2ϩ resequestration, which suggested that changes in skeletal muscle contractile parameters were mediated by alterations in SR proteins, namely a ␤ 2 -agonist-mediated induction of SERCA1 protein levels (36). In addition, salbutamol treatment attenuated the fast twitch-to-slow twitch transformation of myosin heavy-chain (MHC) isoforms, SR protein characteristics, and muscle mechanics that accompany chronic lowfrequency stimulation (CLFS) (10).…”

mentioning

confidence: 99%

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β₂-Agonist administration increases sarcoplasmic reticulum Ca²⁺-ATPase activity in aged rat skeletal muscle

Schertzer¹,

Plant²,

Ryall³

et al. 2005

American Journal of Physiology-Endocrinology and Metabolism

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-Agonist administration increases sarcoplasmic reticulum Ca 2ϩ -ATPase activity in aged rat skeletal muscle. Am J Physiol Endocrinol Metab 288: E526 -E533, 2005. First published October 12, 2004 doi:10.1152/ ajpendo.00399.2004.-Aging is associated with a slowing of skeletal muscle contractile properties, including a decreased rate of relaxation. In rats, the age-related decrease in the maximal rate of relaxation is reversed after 4-wk administration with the ␤ 2-adrenoceptor agonist (␤ 2-agonist) fenoterol. Given the critical role of the sarcoplasmic reticulum (SR) in regulating intracellular Ca 2ϩ transients and ultimately the time course of muscle contraction and relaxation, we tested the hypothesis that the mechanisms of action of fenoterol are mediated by alterations in SR proteins. Sarcoendoplasmic reticulum Ca 2ϩ -ATPase (SERCA) kinetic properties were assessed in muscle homogenates and enriched SR membranes isolated from the red (RG) and white (WG) portions of the gastrocnemius muscle in adult (16 mo) and aged (28 mo) F344 rats that had been administered fenoterol for 4 wk (1.4 mg/kg/day ip, in saline) or vehicle only. Aging was associated with a 29% decrease in the maximal activity (V max) of SERCA in the RG but not in the WG muscles. Fenoterol treatment increased the V max of SERCA and SERCA1 protein levels in RG and WG. In the RG, fenoterol administration reversed an age-related selective nitration of the SERCA2a isoform. Our findings demonstrate that the mechanisms underlying age-related changes in contractile properties are fiber type dependent, whereas the effects of fenoterol administration are independent of age and fiber type.aging; calcium; ␤-adrenoceptor; contractility SARCOPENIA, THE PROGRESSIVE LOSS of skeletal muscle mass with advancing age, is associated with a decline in muscle strength that leads to a loss of functional independence and a reduced quality of life (17). Aging is also associated with a slowing of the time course of skeletal muscle contraction and relaxation (15). These changes can reduce the accuracy and precision of movements, impair the ability to perform simple tasks, and increase the risk of sudden falls and related injuries. Ideally, therapies to prevent or reverse the age-related changes in skeletal muscle should also target the slowing of contraction and relaxation, in addition to preserving or increasing muscle mass and strength.Neurogenic factors, such as motor unit remodeling and denervation, have been implicated in the age-related changes to skeletal muscle (11). However, myogenic factors are also involved, since the slowing of contraction and relaxation occurs before the onset of muscle wasting (18,20,21). Intrinsic changes to skeletal muscle fibers appear to be involved in the deterioration of function with age. Specifically, age-related changes in the proteins regulating Ca 2ϩ handling during excitation-contraction coupling and relaxation have been described (15).Relaxation of skeletal muscle is thought to involve at least three processes: dissociation of Ca 2...

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Salbutamol changes the molecular and mechanical properties of canine skeletal muscle.

Cited by 26 publications

References 37 publications

Pattern of Myosin Heavy Chain Isoforms in Different Fibre Types of Canine Trunk and Limb Skeletal Muscles

Pattern of Myosin Heavy Chain Isoforms in Different Fibre Types of Canine Trunk and Limb Skeletal Muscles

Identification of Myosin Heavy Chain I, IIa and IIx in Canine Skeletal Muscles by an Electrophoretic and Immunoblotting Study

β₂-Agonist administration increases sarcoplasmic reticulum Ca²⁺-ATPase activity in aged rat skeletal muscle

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Salbutamol changes the molecular and mechanical properties of canine skeletal muscle.

Cited by 26 publications

References 37 publications

Pattern of Myosin Heavy Chain Isoforms in Different Fibre Types of Canine Trunk and Limb Skeletal Muscles

Pattern of Myosin Heavy Chain Isoforms in Different Fibre Types of Canine Trunk and Limb Skeletal Muscles

Identification of Myosin Heavy Chain I, IIa and IIx in Canine Skeletal Muscles by an Electrophoretic and Immunoblotting Study

β2-Agonist administration increases sarcoplasmic reticulum Ca2+-ATPase activity in aged rat skeletal muscle

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β₂-Agonist administration increases sarcoplasmic reticulum Ca²⁺-ATPase activity in aged rat skeletal muscle