C. Huchetcadiou et al., HYPOGRAVITY INCREASES CYCLOPIAZONIC ACID SENSITIVITY OF RAT SOLEUS MUSCLE, Journal of applied physiology, 80(4), 1996, pp. 1100-1104
The functional capacity of skeletal muscle sarcoplasmic reticulum was
explored in slow rat soleus muscle after 21 days of hindlimb suspensio
n. The sarcoplasmic reticulum function was assessed in intact and sapo
nin-skinned fibers by using cyclopiazonic acid, a specific Ca2+-adenos
inetriphosphatase inhibitor. After hindlimb unweighting, the sensitivi
ty to cyclopiazonic acid of intact and skinned soleus fibers becomes s
imilar to that found in fast-twitch muscles. This change could be rela
ted to the expression of fast Ca2+-adenosinetriphosphatase-pump protei
n in unloaded soleus muscles and agrees with a transformation of soleu
s muscle from slow- to fast-twitch type. These results also indicate t
hat specific pharmacological tools, hire cyclopiazonic acid, could be
used to analyze subcellular functional changes due to hindlimb unweigh
ting.