A. Hayes et Da. Williams, CONTRACTILE PROPERTIES OF CLENBUTEROL-TREATED MDX MUSCLE ARE ENHANCEDBY LOW-INTENSITY SWIMMING, Journal of applied physiology, 82(2), 1997, pp. 435-439
The beta(2)-agonist clenbuterol has potent anabolic properties in norm
al and denervated muscle and, as such, may be of use in muscle wasting
diseases such as muscular dystrophy. However, potential side effects
such as the transformation of the fiber type pool toward increased pro
portions of fast-twitch fibers must be balanced with the beneficial an
abolic properties. In the present report, we clearly show that extenso
r digitorum longus and soleus muscles from dystrophic mdx mice exposed
to a combination of clenbuterol and low-intensity endurance swimming
exercise did not undergo the slow- to fast-twitch fiber transformation
s caused by clenbuterol administration alone, yet increases in the for
ce-generating capacity of the soleus (30-40%) that resulted fr om the
clenbuterol treatment were maintained after the swimming program. The
increased sensitivity of dystrophin-deficient dystrophic muscle to cle
nbuterol and low-intensity exercise that is evident in this study may
have therapeutic implications in the treatment of muscle wasting disea
ses.