The Effects of Clenbuterol on Skeletal and Cardiac Muscle of Rats when Combined with Aerobic and Anaerobic Exercise

Duncan, N. D.; Lynch, Gordon S.; Jones, D; Williams, D. A.

doi:10.1042/cs087s075

Cited by 2 publications

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“…This drug concentration (30 mg/l) has been previously shown to be effective in promoting maximal growth of several types of muscles (5,19,33). This manner of administering the drug was chosen 1) because it enabled us to avoid manipulation of the HU rats to prevent stress and 2) because water absorption has previously been described to be as effective as injections (9,18). All the rats were individually caged on a 12:12-h light-dark cycle at 23°C room temperature.…”

Section: Animals and Samplesmentioning

confidence: 99%

Effects of β₂-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Ricart-Firinga

Stevens

Canu

et al. 2000

American Journal of Physiology-Cell Physiology

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The effects of clenbuterol beta(2)-agonist administration were investigated in normal and atrophied [15-day hindlimb-unloaded (HU)] rat soleus muscles. We showed that clenbuterol had a specific effect on muscle tissue, since it reduces soleus atrophy induced by HU. The study of Ca(2+) activation properties of single skinned fibers revealed that clenbuterol partly prevented the decrease in maximal tension after HU, with a preferential effect on fast-twitch fibers. Clenbuterol improved the Ca(2+) sensitivity in slow- and fast-twitch fibers by shifting the tension-pCa relationship toward lower Ca(2+) concentrations, but this effect was more marked after HU than in normal conditions. Whole muscle electrophoresis indicated slow-to-fast transitions of the myosin heavy chain isoforms for unloaded and for clenbuterol-treated soleus. The coupling of the two latter conditions did not, however, increase these phenotypical transformations. Our findings indicated that clenbuterol had an anabolic action and a beta(2)-adrenergic effect on muscle fibers and appeared to counteract some effects of unloading disuse conditions.

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Section: Animals and Samplesmentioning

confidence: 99%

Effects of β₂-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Ricart-Firinga

Stevens

Canu

et al. 2000

American Journal of Physiology-Cell Physiology

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“…The large doses of mass-building drugs taken by these athletes may also be life threatening, considering the evidence for myocardial necrosis and decreased cardiac performance after chronic highdose b 2 -agonist therapy (15). Indeed, in other related experiments, Duncan and colleagues (7,8) have observed a decrease in the exercise performance of chronic clenbuterol-treated rats during 2-h swimming sessions and short-term high-intensity treadmill-running bouts that appear to be attributed to decreased cardiac performance. In this study, 1 h of low-intensity unweighted swimming was comfortably managed by the clenbuterol-treated mice, and no attempt was made to subject the clenbuterol-treated mice to more intense training.…”

Section: Effect Of Clenbuterol On Muscle Fiber Type Proportionsmentioning

confidence: 99%

Effects of β₂-agonist administration and exercise on contractile activation of skeletal muscle fibers

Lynch

Hayes

Campbell

et al. 1996

Journal of Applied Physiology

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Clenbuterol, a beta 2-adrenoceptor agonist, has therapeutic potential for the treatment of muscle-wasting diseases, yet its effects, especially at the single-fiber level, have not been fully characterized. Male C57BL/10 mice were allocated to three groups: Control-Treated mice were administered clenbuterol (2 mg.kg-1. day-1) via their drinking water for 15 wk; Trained-Treated mice underwent low-intensity training (unweighted swimming, 5 days/wk, 1 h/day) in addition to receiving clenbuterol; and Control mice were sedentary and untreated. Contractile characteristics were determined on membrane-permeabilized fibers from the extensor digitorum longus (EDL) and soleus muscles. Fast fibers from the EDL and soleus muscles of Treated mice exhibited decreases in Ca2+ sensitivity. Endurance exercise offset clenbuterol's effects, demonstrated by similar Ca2+ sensitivities in the Trained-Treated and Control groups. Long-term clenbuterol treatment did not affect the normalized maximal tension of fast or slow fibers but increased the proportion of fast fibers in the soleus muscle. Training increased the proportion of fibers with high and intermediate succinate dehydrogenase activity in the EDL and soleus muscles, respectively. If clenbuterol is to be used for treating muscle-wasting disorders, some form of low-intensity exercise might be encouraged such that potentially deleterious slow-to-fast fiber type transformations are minimized. Indeed, in the mouse, low-intensity exercise appears to prevent these effects.

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The Effects of Clenbuterol on Skeletal and Cardiac Muscle of Rats when Combined with Aerobic and Anaerobic Exercise

Cited by 2 publications

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Effects of β₂-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Effects of β₂-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Effects of β₂-agonist administration and exercise on contractile activation of skeletal muscle fibers

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The Effects of Clenbuterol on Skeletal and Cardiac Muscle of Rats when Combined with Aerobic and Anaerobic Exercise

Cited by 2 publications

References 0 publications

Effects of β2-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Effects of β2-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Effects of β2-agonist administration and exercise on contractile activation of skeletal muscle fibers

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Effects of β₂-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Effects of β₂-agonist clenbuterol on biochemical and contractile properties of unloaded soleus fibers of rat

Effects of β₂-agonist administration and exercise on contractile activation of skeletal muscle fibers