Hypogravity increases cyclopiazonic acid sensitivity of rat soleus
muscle.
Corinne, Huchet-Cadiou, Bonnet Val[acute]erie, Meme William, and
L[acute]eoty Claude.
URA CNRS 1340, Laboratory of General Physiology, Faculty of
Sciences, 2
rue de la Houssini[grave]ere, F-44072 Nantes Cedex 03 FRANCE
APStracts 2:0529A, 1995.
The functional capacity of skeletal muscle sarcoplasmic reticulum (SR)
was explored in slow rat soleus muscle after 21 days of hindlimb
suspension. The SR function was assessed in intact and saponin
skinned fibers using cyclopiazonic acid, a specific Ca2+ATPase
inhibitor. Following hindlimb unweighthing, the sensitivity to
cyclopiazonic acid of intact and skinned soleus fibers becomes
similar to that found in fast-twitch muscles. This change could be
related to the expression of fast Ca2+ ATPase pump protein in
unloaded soleus muscles and agrees with a transformation of soleus
muscle from slow- to fast-twitch type. These results also indicate
that specific pharmacological tools, like cyclopiazonic acid could be
use to analyse subcellular functional changes due to hindlimb
unweigthing
Received 20 April 1995; accepted in final form 13 November 1995.
APS Manuscript Number A429-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95