Key result
Hindlimb suspension in rats reduces soleus maximal tension and alters calcium threshold and contraction kinetics.
Why the study?
The contractile properties of atrophied rat soleus muscle after hindlimb suspension were not fully characterized at the level of single skinned fibers.
Does 15 days of hindlimb suspension alter the contractile properties of rat soleus muscle?
Does 15 days of hindlimb suspension alter the contractile properties of rat soleus muscle?
Hindlimb suspension for 15 days alters the mechanical properties of slow-twitch rat soleus muscle to more closely resemble fast-twitch muscle.
Answers are grounded in this paper and cite their sources.
Hypothesis-generating for disuse atrophy mechanisms; leaves open translation to human cardiac or skeletal muscle function.
The properties of the contractile elements interacting to develop force in atrophied rat soleus muscle were studied by using single skinned fibers, which permitted direct access to the contractile apparatus. Muscle atrophy was induced by 15 days of hindlimb suspension. Suspension resulted in a decrease of maximal tension relative to an important decline in fiber diameter. Ca affinity of the contractile proteins was not changed insofar as the tension-pCa relationship was not shifted along the pCa axis. However, after hindlimb suspension 1) the value of the Hill coefficient from the tension-pCa curve was found to be higher, 2) a higher Ca threshold for activation was reported, and 3) a significant increase in contraction kinetics was described. All these results suggested that after suspension the mechanical properties of the slow-twitch soleus appeared to resemble more closely those of a fast-twitch muscle. Our results were in complete agreement with published histochemical data.
No takes yet. Share an insight, caveat, or question.
Stevens et al. (1990) studied Muscle atrophy. Hindlimb suspension was evaluated on Contractile properties (maximal tension, Ca affinity, Hill coefficient, Ca threshold, contraction kinetics). 15 days of hindlimb suspension in rats decreased maximal tension and fiber diameter, increased the Hill coefficient and Ca threshold, and increased contraction kinetics in the soleus muscle.
Synapse has enriched 10 related papers. Consider them for comparative context: