Preservation of denervated muscle form and function by clenbuterol in a rat model of peripheral nerve injury

The effects of clenbuterol in preserving the form and function of muscle af ter unilateral sciatic nerve division and epineural repair were investigate d in a rat model. The drug (a beta (2)-adrenoceptor agonist) was administer ed daily for six weeks by gastric gavage (10 mug/kg body weight), interrupt ed every 5 days by a 2 day omission of dosing to avoid drug desensitization . Clenbuterol reduced the loss of wet weight, total protein, muscle fibre c ross sectional area and (in part) contractile forces in denervated hindlimb muscles, with most effects lasting until reinnervation. The effects were d ependent on muscle type, with slow-twitch oxidative muscle (soleus) and mix ed-fibre (gastrocnemius) showing greater sensitivity to the drug than fast- twitch muscle (extensor digitorum longus). Anabolic effects on the contrala teral innervated muscles tended to be small. The results suggest a potentia l for the adjuvant use of selective beta -adrenoceptor agonists in the mana gement of peripheral nerve injuries in humans.